A jury convicted the defendants, a dairy farmer and his wife, of two federal crimes: (1) “willfully holding to involuntary servitude” two retarded farm workers,1 and (2) conspiring to deprive the workers of their constitutional right to be free from “involuntary servitude” as guaranteed by the Thirteenth Amendment.2 Their son was *1188also convicted on the conspiracy charge. On appeal the defendants contend that the court below erred in broadly defining “involuntary servitude” to include purely psychological coercion in addition to slavery, peonage, serfdom and other forms of physical or legal coercion.3 They also argue that the court below erred in admitting expert psychological testimony tending to show that the two victims were held in servitude through “involuntary conversion” or “brainwashing.” After reconsidering the legislative development and purpose of the two nineteenth century criminal statutes in question, we agree with the defendants that the court below erred in defining involuntary servitude too broadly, and we agree that the psychological testimony should not have been admitted.
I.
The government does not contend that the two men were forcibly held to work on the farm. In its en banc brief, the government concedes that the men were “free to leave,” “came back on their own accord” but “believed they had no place else to go.” Brief for Appellee at 15. Nevertheless the government contends that the defendants’ efforts to isolate the men from contact with the outside world through a pattern of verbal and physical abuse, as well as harsh living and working conditions, exerted a form of extreme psychological coercion upon the men given their low intelligence. According to the government’s theory of the case, this coercive conduct, referred to as “involuntary conversion” or “brainwashing,” is sufficient to constitute “involuntary servitude.”
The servants, Robert Fulmer and Louis Molitoris, lived and worked on the Kozminski dairy farm for more than ten years as general farm laborers. They brought in the cows for milking twice a day, cleaned up the barn during milking, repaired and cleaned farm equipment, hauled feed for the cows and did other farm chores. Dr. Harley Stock, a clinical psychologist, found that Fulmer’s I.Q. is 67 and Molitoris’ is 60.
Robert Fulmer lived in foster homes until he was eleven years old. He then entered a training school for boys where he learned to do general farm work. In the 1950’s and 60’s, he worked as a farm hand on various farms. One evening in 1967, Ike and Margarethe Kozminski and their son, Michael, picked up Fulmer on a road near the farm where he was working. Fulmer agreed to work for them in exchange for food and a place to live. Fulmer worked on the Kozminski’s dairy farm in Stockbridge, Michigan until 1968 when he moved to the Kozminski’s farm in Chelsea, Michigan.
The other farm worker, Louis Molitoris, had been institutionalized at the Ypsilanti State Hospital and had been a groundskeeper at a cemetery in Ann Arbor, Michigan prior to coming to the Kozminski’s farm. In the early 1970’s Molitoris was unemployed and lived on the streets of Ann Arbor. During the winter, Ike Kozminski, who also ran a barber shop, occasionally allowed Molitoris to come into his shop to get warm and to sleep. Ike Kozminski thereafter offered to give Molitoris a place to stay, food and cigarettes if he would work on the Kozminski dairy farm. Molitoris agreed.
The government offered testimony about the condition of Fulmer and Molitoris’ life on the farm including their living quarters, their physical treatment, their isolation on the farm and how the Kozminski’s held them out to the community. Several witnesses testified that the men lived in squal- or. The trailer they occupied was filthy having no running water, a broken refrigerator and maggot-infested food. Never*1189theless, the men apparently had working bathroom facilities nearby. Moreover, Fulmer and Molitoris were responsible for cleaning their own quarters. Mrs. Kozminski cooked meals for Fulmer when he lived at the Stockbridge farm until he told her he wanted to cook for himself. Thereafter, the Kozminskis provided Fulmer and later Molitoris with groceries.
The testimony about the men’s physical treatment includes neighbors’, tenants’ and co-workers’ descriptions of the men being slapped, choked and kicked on several occasions. John and Margarethe Kozminski denied striking the men. Ike Kozminski testified that he kicked Fulmer for hitting a cow with a crowbar and he threw a pail at him for not repairing a leak. Ike also testified that he hit Molitoris “as hard as I could,” after Molitoris hit him while they were loading pigs.
The men often drove a tractor on the road. Several witnesses also testified that they had seen the men in town or in other locations away from the farm. On occasion they left the farm to visit family members or friends. They sometimes “sneaked away” from the farm. They “hid” with neighbors. Two witnesses testified that Ike, Margarethe and John Kozminski brought the men back to the farm and discouraged them from leaving. Four witnesses testified that the men asked them to remove them from the farm.
The government contends that the Kozminskis tried to isolate the men from their families and the outside world. The Kozminskis told visitors on the farm to ignore Fulmer and Molitoris and the men were told not to speak to visitors. Margarethe Kozminski pulled a telephone off the wall in the bam when Fulmer used it to call a neighbor. Shortly after Molitoris moved to the farm, Ike and Margarethe apparently ordered him to bum the trunk which contained his belongings, including family pictures, allegedly because they contained cockroaches. Ike Kozminski told Fulmer his brothers and sister did not care about him. Margarethe discouraged Fulmer’s sister and brother from visiting him. She also discouraged Molitoris’ sister from calling him.
Witnesses testified that the Kozminskis told neighbors and visitors to the farm the men were in their custody and were wards of the state, although Mrs. Kozminski denied these allegations. Both she and Ike Kozminski testified that at one time they had a farm hand who was a ward of the state.
The court below gave a general charge on involuntary servitude. Under its instructions, the jury could convict the defendants of holding the workers to involuntary servitude through psychological as well as physical coercion. It did not set out a specific theory of involuntary servitude or confine the jury’s deliberations to a particular definition of the crime. Instead, it left the definition of “involuntary servitude” up to the jury under a general charge. This Court granted en banc review vacating the judgment of a three-judge panel of the Court, Judge Krupansky, dissenting, which had affirmed the convictions and judgments of the court below with respect to each defendant.
II.
The Courts of Appeals are squarely in conflict in their interpretation of the words of § 1584, “whoever knowingly and willfully holds [another] to involuntary servitude.” The two polar cases are United States v. Shackney, 333 F.2d 475 (2d Cir.1964) (Friendly, J.), and United States v. Mussry, 726 F.2d 1448 (9th Cir.), cert. denied, 469 U.S. 855, 105 S.Ct. 180, 83 L.Ed.2d 114 (1984) (Reinhardt, J.). In Shackney, the Second Circuit gave “involuntary servitude” a narrow construction. The court effectively limited the concept to slavery and peonage: the use or threat of physical punishment to enforce work, and the use of state-imposed legal coercion to make a debtor work for his creditor.
The Ninth Circuit, like the trial court below and the panel decision of our Court, adopts a more expansive interpretation that includes the use of purely psychological coercion. The Ninth Circuit opinion, like the jury instruction of the court below, *1190leaves the precise nature of the crime to the jury under a general charge: “The crucial factor is whether a person intends to and does coerce an individual into his service by subjugating the will — ” 726 F.2d at 1453. Although the Second and the Ninth Circuits differ on whether psychological coercion can cause “involuntary” servitude within the meaning of the statute, both courts agree that the coercion — physical, legal or psychological — must produce in the victim the same basic state of mind. The coercion must cause the victim to believe that he has “no alternative,” Mussry, 726 F.2d at 1453, or “no way to avoid” the labor. Shackney, 333 F.2d at 486.
The difficulty of the statutory construction question presented and the lack of agreement among the Circuits have prompted us to reread and reconsider the unusual legislative development and history of § 1584. The history of the statute begins in 1807 when Congress passed a statute prohibiting the slave trade, and it ends in 1948 when Congress, while codifying the criminal laws into Title 18, combined the slave trade and involuntary servitude statutes into the present language of § 1584. (The text of these statutes and their historical development is summarized in a chart attached hereto as an Appendix.)
The words, “hold to involuntary servitude” as used in § 1584, emanate directly from an 1874 statute designed to outlaw the so-called “Padrone ” system of importing, selling and exploiting the labor of Italian children in the United States. The 1874 Padrone statute punished “whoever shall knowingly and wilfully bring into the United States ... any person inveigled or ... kidnapped ... with intent to hold ... to any involuntary service,” or “cause to be sold, into any condition of involuntary servitude, any other person.” The 1874 statute goes on to say that “every person who shall knowingly and wilfully hold to involuntary service any [such] person ... shall be deemed guilty of a felony____” The original statute is narrower than the present § 1584 because the old statute requires that the victim be “imported” or “sold” prior to the servitude, whereas § 1584 eliminates the requirement of importation or sale prior to the holding of involuntary servitude.
The metamorphosis of the Padrone statute into its present form took place in two stages. The 1909 general revision of the criminal law altered the language of the old statute slightly but continued the requirement of importation or sale. At the time of this revision, Congress believed that the broad language of the 1874 statute should be retained because the Padrone system and other similar forms of exploitation still flourished. This sentiment is vividly illustrated by Senator Henry Cabot Lodge’s remarks during debate on the 1909 revision:
The fact, Mr. President, that slavery has long ceased to exist in this country does not seem to me to justify the abolition of statutes such as [these]____There are people who may be guilty of the crimes which those statutes are designed to punish. The Senator referred to a case on the Pacific coast where the Chinese were involved some years ago. I was on a committee of the Senate which investigated the question of the importation of Italian boys into this country____ I happen to be one of those who made investigation into what was known as the padrone system. The padrones were men in New York who brought boys out from Italy and let them out for various purposes — shoeblacks, and one thing and another of that sort — and the boys were held in a condition of practical slavery. We have tried to meet some of these difficulties by our immigration laws, but the fact that slavery has been abolished, the fact that it is a crime, does not seem to me to make it desirable, therefore, to do away with all the statutes which were designed to punish the crime and which make it a crime.
The declaration of the thirteenth amendment to the Constitution is not of itself sufficient ... so I think that statutes of similar nature on the statute books of the United States should remain in order to prevent crimes of that character, whether they occur among the Chinese immigrants or *1191whether among the padrones who exist in New York and in some of our other large cities.
42 Cong.Rec. 1122 (1908) (statement of Sen. Lodge) (emphasis supplied).
Senator Heyburn, the chief proponent of the penal law revision, also argued for the reenactment of the Padrone statute in order to protect classes of individuals who “can not protect themselves”:
[T]his criminal statute is intended only to enable the law to reach those who come here without being a party to their coming here or without being a party to the disposition of their services or the control of their rights, whether they be children of irresponsible years and conditions or whether they be people who, because of their environment or the conditions of their lives, can not protect themselves.
42 Cong.Rec. 1115 (1908) (statement of Sen. Heyburn) (emphasis supplied).
After the reenactment and codification in 1909, the final stage in the metamorphosis of § 1584 occurred in 1948. The old slave trade statute and the Padrone statute were combined into § 1584, and the elements of the crime were changed. The combined statute continues to punish those who import, or buy or sell a person with intent to hold to involuntary servitude.4 In addition, it also punishes those who just hold a person to involuntary servitude without kidnapping, importation or selling. The latter was not possible under either the old slave trade statute or the old Padrone statute.5
None of the cases listed above, which attempt to define or give content to a standard of involuntary servitude under § 1584, rely on the legislative purpose of the 1874 Padrone statute or its judicial interpretation. Judge Friendly in the Shackney opinion acknowledges this historical development but establishes the narrow Second Circuit standard — limited to physical and legal coercion — without drawing content from the old Padrone statute. Judge Friendly reasoned that since the 1948 codification of § 1584 “constitutes ‘positive law,’ ... our search must be for the meaning of § 1584 rather than of its two parents.” 333 F.2d at 482. Since Judge Friendly believed the 1948 enactment “extinguished” this history, he did not draw on the old statute in framing a standard under § 1584. Neither do any of the other cases decided to date.
We believe it is a mistake to read § 1584 in isolation from the older statutes which produced it. Without the earlier statutes, particularly the Padrone statute, and the legislative purpose which animated them, § 1584 would not exist today. Section 1584 does not appear to have any legislative purpose or history aside from that associated with the parent statutes. We therefore believe it necessary to define § 1584 in terms of the nature of the evil which the two predecessor statutes sought to prevent.
Specifically, the legislative history surrounding the Padrone statute suggests that it was designed to reach a broader class of exploitation than was previously covered by laws dealing with slavery, involuntary servitude and peonage. The earlier laws clearly covered circumstances involving the use or threatened use of law or physical force to constitute a “holding in involuntary servitude.” The Padrone statute was aimed at a form of exploitation that was more subtle: securing the services of an individual who is incapable of giving legally valid consent.
Judge Blatchford, writing two years prior to his elevation to the Supreme Court, illustrated this purpose of the Padrone statute in United States v. Ancarola, 1 F. 676 (C.C.S.D.N.Y.1880). In affirming An*1192carola’s conviction for violating the Pa-drone statute, Judge Blatchford addressed the propriety of the trial court’s jury charge which had instructed that the age of the victims be taken into account in determining the voluntariness of their employment. Holding that age was indeed a relevant factor in considering the validity of the children’s consent, Judge Blatchford emphasized their unfortunate circumstances:
[T]he children, in serving the defendant as street musicians, for his profit, to the injury of their morals, subject to his control, could not properly be considered as rendering him voluntary service. They were incapable of exercising will or choice affirmatively on the subject. They were cast off by their parents, in violation of the law of Italy, and their being in this country at all with the defendant was, on all the facts, really involuntary on their parts, although the sham form of their consent was gone through with.
Ancarola, 1 F. at 683.
In our view, Ancarola thus stands for the important proposition that service can be involuntary where there exists “sham consent” as a result of several forms of legal incapacity.6 The Ancarola standard was therefore not limited only to physical or legal coercion.
As discussed above, Judge Friendly does not focus on the Padrone statute and the interpretation thereof. The Shackney standard thus fails to address the full range of conduct proscribed by § 1584 such as that held criminal in Ancarola. In establishing our standard, we have attempted to give effect to the 1874 statute in a way that is consistent with the principle of narrow construction of criminal statutes. Accordingly, the standard we adopt modifies the Shackney standard to include the type of servitude outlawed in the 1874 statute as interpreted in the Ancarola case.
We conclude that a “holding to involuntary servitude” occurs when (a) the servant believes that he or she has no viable alternative but to perform service for the master (b) because of (1) the master’s use or threatened use of physical force, or (2) the master’s use or threatened use of state-imposed legal coercion (ie., peonage7), or (3) the master’s use of fraud or deceit to obtain or maintain services where the servant is a minor, an immigrant or one who is mentally incompetent. In cases in the last category, it must be shown that the servant is under a disability to recognize or resist the master's fraud or deceit because of the servant’s vulnerability as a member of one of these classes. In order to be found guilty under the statute, the master must intentionally hold the victim to involuntary servitude in one of these proscribed ways.
This definition protects those whose services have been wrongfully obtained and who believe that they have no viable way *1193of avoiding the services demanded. The physical force and legal coercion prongs of our standard follow Shackney and its progeny in the Fourth, Fifth and Eleventh Circuits which outlaw various forms of slavery, serfdom and peonage.8 The third prong emanates directly from the history of § 1584 and is designed to protect extremely vulnerable classes of individuals covered by the 1874 Padrone statute, classes similar to those who lack the capacity to contract at common law.
The Restatement (Second) Contracts § 12(2) discusses capacity to contract in relevant part as follows: “A natural person who manifests assent to a transaction has full legal capacity to incur contractual duties thereby unless he is (a) under guardianship, or (b) an infant, or (c) mentally ill or defective____” We also include immigrants because of the express purpose of the predecessor statute to § 1584, the Pa-drone statute.9 This interpretation is supported by Senator Heyburn’s statement quoted above that the slave trade laws were intended to protect “children of irresponsible years and conditions ... [and] people who, because of their environment or the condition of their lives, can not protect themselves.” 42 Cong.Rec. 1115 (1908).
The District Court did not limit the masters or the servants covered by the statute to the narrow categories described above. The District Court’s rulings and instructions would appear to criminalize general psychological coercion without fraud, deceit, force or legal coercion and would include all individuals within the covered class of victims subject to psychological coercion, not just the particularly vulnerable classes referred to in the legislative history of the statute. The Ninth Circuit’s, the panel’s and the District Court’s broad definition might appear to place the day-to-day activities of cult groups, communes and religious orders within the coverage of the statute. Our standard would criminalize these activities only if the group engaged in one of the proscribed types of conduct.
We reverse and remand the case for new trial for these reasons. After a careful review of the evidence, we conclude that we should not order a judgment of acquittal, as the defendants contend, because there is evidence from which a jury could conclude (1) that the victims believed that they had no viable alternative but to perform the labor in question, and (2) that the victims were mentally incompetent and the defendants practiced fraud and deceit in maintaining the victims’ services.
III.
The Kozminskis also contest the admissibility of the expert psychological testimony *1194presented at trial by Dr. Harley Stock. Dr. Stock testified that given the victims’ low mentality, the psychological pressures exerted upon them created an “involuntary conversion” to complete dependency akin to “captivity syndrome,” a psychological phenomenon arising from prolonged physical captivity. This testimony was offered to show that Fulmer and Molitoris were the victims of psychological coercion and had been “brainwashed” into serving the Kozminskis. This evidence is inadmissible because a foundation was not laid to establish its conformity to a generally accepted explanatory theory.
The admissibility of expert testimony is governed by Rule 702 of the Federal Rules of Evidence. Rule 702 states:
If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise.
For expert testimony to be admissible under Rule 702, a four-part test must be met: (1) a qualified expert; (2) testifying on a proper subject; (3) in conformity to a generally accepted explanatory theory; (4) the probative value of which outweighs any prejudicial effect. United States v. Green, 548 F.2d 1261, 1268 (6th Cir.1977) (emphasis supplied); United States v. Smith, 736 F.2d 1103, 1105 (6th Cir.), cert. denied, 469 U.S. 868, 105 S.Ct. 213, 83 L.Ed.2d 143 (1984). The elements of this four part test under Green constitute preliminary questions for purposes of Rule 104(a) of the Federal Rules of Evidence. As such, the trial judge must find that the expert and the proposed testimony meet the Green criteria prior to admitting the testimony: this is not a jury question. See Fed.R.Evid. 104 advisory committee’s note; 11 J. Moore & H. Bendix, Moore’s Federal Practice, § 702.10[3] (2d ed. 1985).10
It does not appear that a proper foundation was laid under the third element of the Green test. The criticisms voiced by Drs. Emanuel Tanay and Robert Walsh suggest that Dr. Stock’s “involuntary conversion” theory is not scientifically-recognized. Dr. Tanay stated that he had never heard of Dr. r Stock’s “involuntary conversion” theory prior to trial. Dr. Ta-nay went on to note that the phenomenon of “ideological conversion” which is associated with captivity syndrome would have “no application” to the present situation, and that it would be “ridiculous” to attempt to apply it. Dr. Walsh testified that he considered involuntary conversion to be equivalent to brainwashing and opined that Dr. Stock’s diagnosis “exceeded sound professional practice.”
Dr. Stock attempted to establish his theory by incorporating the well-established “captivity syndrome.” Although captivity syndrome is a generally accepted explanatory theory, it has no application to this case. Drs. Tanay and Stock both agreed that “captivity syndrome” has ten necessary elements:
(1) Prolonged captivity; (2) continuous around the clock supervision, such as guarding; (3) an isolated environment; (4) removal of all supports; (5) an attack on personality; (6) a lack of privacy; (7) assault upon the total personality; (8) a systematic use of reward and punishment; (9) a tearing of the fabric of the personality; and (10) the building up of a new personality.
These factors are not present in this case. There is no evidence that Fulmer and Molitoris were subjected to conditions equivalent to those described above. For example, there was no evidence of actual captivity, a necessary element of captivity syndrome. This list of conditions describes the process employed by the Chinese to “brainwash” prisoners of war during the Korean conflict. As bad as conditions on the Kozminski’s dairy farm are alleged to be, they fall short of those found in a Chinese prison camp. Accordingly, captivity syndrome is inapplicable as a matter of law given the facts of this case. There*1195fore, a proper foundation was not laid for Dr. Stock’s testimony under the third element of the Green standard and it should have been excluded.
Accordingly, the judgment of the District Court is reversed and the ease remanded for a new trial under the standards enunciated herein.
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. Section 1584, Title 18, punishes as a felony:
"Whoever knowingly and willfully holds to involuntary servitude or sells into any condition of involuntary servitude, any other person for any term, or brings within the United States any person so held____”
. Section 241, Title 18, states the conspiracy offense as follows: "If two or more persons conspire to injure, oppress, threaten, or intimidate any citizen in the free exercise or enjoyment of any right or privilege secured to him by the Constitution or laws of the United States____”
The Thirteenth Amendment reads: "Section 1. Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction.
Section 2. Congress shall have power to enforce this article by appropriate legislation.”
. The trial court instructed the jury to incorporate the definition of involuntary servitude from § 1584 into § 241 which encompasses the Thirteenth Amendment. The parties do not challenge the process of incorporating the statutory definition into the constitutional definition, although the Kozminskis argue that the § 1584 definition which was incorporated was incorrect. For the reasons stated below, we agree that the § 1584 standard was incorrect, -and it should not have been applied in either context. We do not reach the question of whether it was proper for the trial court to use the same standard for § 241 and § 1584 since this issue was not raised by the parties.
. See supra, note 1.
. This expansion was not inadvertent. The revision notes to § 1584 indicate that Congress deliberately eliminated the kidnapping requirement which had been a predicate to criminal liability in the predecessor statutes. 18 U.S.C. § 1584 historical and revision notes (1982). other than the changes enumerated in the revision notes, the 1948 recodification was not intended to extinguish the history of these statutes. See S.Rep. No. 1620, 80th Cong., 2d Sess. 1 (1984) ("The original intent of Congress is preserved.”).
. Judge Blatchford set forth the trial court’s jury charge as follows:
After charging that it must be "proved that the accused brought the child here with the intent to hold the child when so brought to involuntary service as a beggar or as a musician,” the court proceeded as follows: “Upon this question the age of the child is important, for, as you know, in regard to some things a child of such tender years is incapable of consent. The nature of the employment to which the accused intended to put the child, the evidence in regard to the arrangement made in Italy, and the ability of the child to labor or play an instrument, are important circumstances in this connection, also, for if you believe from the evidence that the intention of the accused in bringing the child to this country was to employ the child as a beggar or as a street musician, for his own profit, and that such intended employment was one injurious to its morals and inconsistent with its proper care and education, according to its condition, then you will be justified in finding that he intended to hold such child to involuntary service, as charged in the indictment, and this, notwithstanding the fact that the child had consented to the employment in Italy, and that no evidence of a subsequent dissent, while under the control of the accused, has been given."
Ancarola, 1 F. at 682 (emphasis supplied).
. See e.g., Pollock v. Williams, 322 U.S. 4, 64 S.Ct. 792, 88 L.Ed. 1095 (1944); Bailey v. Alabama, 219 US. 219, 31 S.Ct. 145, 55 L.Ed. 191 (1911); IX A. Bickel & B. Schmidt, History of the Supreme Court of the United States: The Judiciary and Responsible Government 1910-21 820-907 (1984).
. The Fourth Circuit requires the "threat of violence or confinement, backed sufficiently by deeds.” United States v. Harris, 701 F.2d 1095, 1100 (4th Cir.), cert. denied, 463 U.S. 1214, 103 S.Ct. 3554, 77 L.Ed.2d 1400 (1983) (quoting United States v. Booker, 655 F.2d 562, 567 (4th Cir.1981)). The Fifth Circuit requires "such fear of physical harm that the victim is affraid to leave, regardless of the victim’s opportunities for escape.” United States v. Bibbs, 564 F.2d 1165, 1168 (5th Cir.1977), cert. denied, 435 U.S. 1007, 98 S.Ct. 1877, 56 L.Ed.2d 388 (1978). According to the Eleventh Circuit, “[t]he use, or threatened use, of physical force to create a climate of fear is the most grotesque example of such coercion." United States v. Warren, 772 F.2d 827, 833-34 (11th Cir.1985), cert. denied, — U.S. -, 106 S.Ct. 1214, 89 L.Ed.2d 326 (1986). The Mussry case is discussed at footnote 9 of the Warren opinion. Since the evidence was apparently sufficient under either standard, the court did not comment on adopting or rejecting Mussry.
. In Section I of his dessenting opinion, Judge Guy derides the inclusion of immigrants in our standard by saying:
Furthermore, the inclusion of "immigrants” as a special class cannot be supported by reference to the Padrone statute as the majority opinion itself suggests. As the Appendix to the majority opinion itself indicates, the antecedent statutes reference "any person inveigled or forcibly kidnapped in any other country, with intent to hold such person so inveigled or kidnapped in confinement or to any involuntary service____" This is hardly the definition of an immigrant.
This same appendix sets forth the title of the statute as follows: "Chap. 464. An act to protect persons of foreign birth against forcible constraint or involuntary servitude.” We think "persons of foreign birth” means "immigrant” and would not include kidnapping an “American in Paris” — a point amply supported by the legislative history set out above.
. The argument that United States v. Green should be overruled is made for the first time in Judge Guy’s en banc dissent, and the court has not considered or voted on this issue.