OPINION
PER CURIAM:Because these cases present the major issue in common, we consolidate them for disposition. The appellants collectively claim that their indictments should have been dismissed because the district court’s charge to the grand jury misstated its constitutional role and function. Separately, they raise issues concerning Apprendi v. New Jersey, 530 U.S. 466, 120 S.Ct. 2348, 147 L.Ed.2d 435 (2000), and prosecu-torial misconduct. We affirm the convictions for the reasons set out below.
FACTS AND PROCEEDINGS BELOW
In 2001, Christopher Leyva-Garcia (“Leyva”) conditionally pled guilty to an indictment charging him with possessing and importing just under fifty kilograms of marijuana. His plea permitted appeal on two issues: the grand jury issue identified above, and an Apprendi claim that the statute under which he was charged was facially unconstitutional, or at least, requires reconstruction such that the government must show mens rea as to drug type and quantity.
In an unrelated incident in the spring of 2001, David Gamboa-Aristegui (“Gamboa”) also conditionally pled guilty to an indictment charging him with importing and possessing over 22 kilograms of marijuana, preserving for appeal the grand jury issue and an Apprendi issue similar to that presented by Leyva’s appeal.
Finally, David Francis Marcucci (“Mar-cucci”) was convicted by a jury in 2001 on a charge of attempted bank robbery. On appeal, Marcucci alleges the same grand jury violation as Leyva and Gamboa; he also contends the prosecutor made inflammatory comments in his closing argument. Marcucci’s grand jury argument stands in a slightly different posture from that of Leyva and Gamboa because he initially was denied the transcript of the charge given to the grand jury. However, the government has conceded that the grand jury charge in Marcucci’s case was essentially the same as those given in the proceedings affecting the other appellants.
STANDARD OF REVIEW
The denial of a motion to dismiss the indictment is reviewed de novo. United States v. Haynes, 216 F.3d 789, 796 (9th Cir.2000). A challenge to the constitutionality of a statute is reviewed de novo. United States v. Serang, 156 F.3d 910, 913 (9th Cir.1998). When an objection occurs, a prosecutor’s allegedly improper closing argument is reviewed under the harmless error standard: the court’s task is to determine whether error occurred, and if so, whether it was harmless. United States v. Laurins, 857 F.2d 529, 539 (9th Gir.1988).
*1159THE CONSTITUTIONALITY OF THE GRAND JURY CHARGE
Gamboa, Leyva and Marcueci (collectively, “appellants”) argue that the district court should have granted their motions to dismiss their indictments, because the charge to the grand jurors in their cases improperly described the grand jury’s constitutional role and functions, thus depriving appellants of their right to a grand jury’s independent exercise of its discretion. Their specific complaint is that the charge did not tell the grand jury that it could refuse to indict them even if there was probable cause to support an indictment.
In each case, the district court gave almost verbatim the model charge that the Administrative Office of the United States Court recommends be given to new grand juries at the beginning of their service,1 which includes the following passages:
[I]t is important that you listen very carefully to these instructions at this time ... I think they’ll outline for you what your responsibilities are, and they will be of great assistance to you in discharging your duties.
The purpose of the Grand Jury is to determine whether there is sufficient evidence to justify a formal accusation against a person.
[Y]our task is to determine whether the government’s evidence as presented to you is sufficient to cause you to conclude that there is probable cause to believe that the accused is guilty of the offense charged. To put it another way, you should vote to indict where the evidence presented to you is sufficiently strong to warrant a reasonable person’s believing that the accused is probably guilty of the offense with which the accused is charged.
You cannot judge the wisdom of the criminal laws enacted by Congress, that is, whether or not there should or should not be a federal law designating certain activity as criminal. That is to be determined by Congress and not by you. Furthermore, when deciding whether or not to indict, you should not be concerned about punishment in the event of conviction. Judges alone determine punishment.
If past experience is any indication of what to expect in the future, then you can expect candor, honesty and good faith in matters presented by the government attorneys.2
The Propriety of the Charge
Appellants claim the model charge is unconstitutional because it does not explain to the grand jurors that they can refuse to indict even if they find probable cause. Whether this standard charge is constitutional is a matter of first impression in this or any other circuit.
We note initially that the language of the standard grand jury charge does not state that the jury “shall” or “must” indict, but merely that it “should” indict, in the event that it finds probable cause. The language does not eliminate discretion on the part of the grand jurors. The appellants acknowledge that, but insist the charge must do more, and must specifically tell the grand jury that it has no obligation to charge if it finds probable cause.
The grand jury clause of the Fifth Amendment, states “No person shall be held to answer for a capital, or otherwise *1160infamous crime, unless on a presentment or indictment of a Grand Jury.”3 The Constitution contains no language requiring the grand jury to be told that it can refuse to indict if probable cause is found. Appellants’ argument that such language is constitutionally required rests on inapplicable statements in a Supreme Court case and on appellants’ mistaken construction of the history of the grand jury.
In Vasquez v. Hillery, 474 U.S. 254, 106 S.Ct. 617, 88 L.Ed.2d 598 (1986), a black defendant convicted of first-degree murder filed a petition for habeas corpus, raising an equal protection challenge to the California grand jury that indicted him, because blacks were excluded from the grand jury. Citing “a doctrine of equal protection jurisprudence first announced in 1880 ... requiring reversal of the conviction of any defendant indicted by a grand jury from which members of his own race were systematically excluded,” id. at 255, 106 S.Ct. 617, the Court affirmed the district court’s reversal of the defendant’s conviction, noting “the need for such a rule is as compelling today as it was at its inception.” Id. at 266, 106 S.Ct. 617. In the course of following its longstanding precedent that racial “discrimination in the grand jury undermines the structural integrity of the criminal tribunal itself, and is not amenable to harmless-error review,” the Court explained:
even if a grand jury’s determination of probable cause is confirmed in hindsight by a conviction on the indicted offense, that confirmation in no way suggests that the [racial] discrimination did not impermissibly infect the framing of the indictment and, consequently, the nature or very existence of the proceedings to come.
When constitutional error calls into question the objectivity of those charged with bringing a defendant to judgment, a reviewing court can neither indulge a presumption of regularity nor evaluate the resulting harm.
Id. at 263-64, 106 S.Ct. 617.
Vasquez establishes that racial discrimination in the selection of a grand jury is a “systematic flaw in the charging process,” id. at 264, 106 S.Ct. 617, a flaw that undermines the court’s confidence in the objectivity- — the essential fairness — of the grand jury, even where a subsequent conviction is ample evidence of probable cause. Appellants seek to establish another “systematic flaw in the charging process” justifying automatic reversal: the failure to charge the grand jury that it has the power to refuse to indict when probable cause exists.
Appellants base their argument on the following language in Vasquez about the function of the grand jury:
The grand jury does not determine only that probable cause exists to believe that a defendant committed a crime, or that it does not. In the hands of the grand jury lies the power to charge a greater offense or a lesser offense; numerous counts or a single count; and perhaps most significant of all, a capital offense or a noncapital offense — all on the basis of the same facts. Moreover, “[t]he grand jury is not bound to indict in every case where a conviction can be obtained.” United States v. Ciambrone, *1161601 F.2d 616, 629 (2d Cir.1979) (Friendly, J., dissenting).
Id. at 263, 106 S.Ct. 617 (emphasis added).
This language — dictum quoting a dissent in a Second Circuit case — does not establish a constitutional right to have the grand jury charge include a statement that although the grand jury’s function is to determine whether probable cause exists, it nevertheless has unlimited discretion to decide whether to indict even when it finds probable cause.4 Instead, the quotation from Vasquez describes powers that grand juries have exercised at certain times in history — powers that are not eliminated by the grand jury charge that appellants challenge, with its statement that the grand jury “should” indict if it finds probable cause.
The grand jury was intended to shield individuals against unfounded accusations:
Historically, [the grand jury] has been regarded as a primary security to the innocent against hasty, malicious and oppressive persecution; it serves the invaluable function in our society of standing between the accuser and the accused, whether the latter be an individual, minority group, or other, to determine whether a charge is founded upon reason or was dictated by an intimidating power or by malice and personal ill will.
Wood v. Georgia, 370 U.S. 375, 390, 82 S.Ct. 1364, 8 L.Ed.2d 569 (1962). The Supreme Court has repeatedly emphasized that the grand jury protects the individual by requiring probable cause to indict. See United States v. Williams, 504 U.S. 36, 47, 51, 112 S.Ct. 1735, 118 L.Ed.2d 352 (1992) (“[T]he whole theory of [the grand jury’s] function is that it ... serve[s] as a kind of buffer or referee between the government and the people .... to assess whether there is adequate basis for bringing a criminal charge.”); United States v. Dionisio, 410 U.S. 1, 16-17, 93 S.Ct. 764, 35 L.Ed.2d 67 (1973) (grand jury’s “mission is to clear the innocent, no less than to bring to trial those who may be guilty”); Branzburg v. Hayes, 408 U.S. 665, 686-87, 92 S.Ct. 2646, 33 L.Ed.2d 626 (1972) (“[t]he ancient role of the grand jury ... has the dual function of determining if there is probable cause to believe that a crime has been committed and of protecting citizens against unfounded criminal prosecutions.”).
The grand jury originated in England, where it replaced the earlier practice of bringing of criminal charges by private *1162complaint, by calling together sixteen men to decide who should be charged. Accusations were not brought to the grand jury by a prosecutor; the jurors themselves brought with them names of those suspected of violating the law. See Andrew D. Leipold, Why Grand Juries Do Not (And Cannot) Protect the Accused, 80 CORNELL L. REV. 260, 280-81 (1995). English grand juries in 1681 refused to issue treason indictments despite great pressure from the king, although a reconstituted grand jury later returned the indictments sought by the Crown. Id. at 282. When the grand jury system came to America with the colonists, it thus carried at least some reputation for independence, a reputation it seemed to confirm when grand juries refused to indict John Peter Zenger, a newspaper publisher, for libel; although Zenger was eventually prosecuted by government information, he was found not guilty. Id. at 284.
Before independence, the grand jury at times stood between the colonies and the Crown by refusing to indict colonists for what the jury considered oppressive rules, such as the tax laws. Id. at 285. The incorporation of the Grand Jury clause into the Fifth Amendment occurred after little debate, and the grand jury did not show significant independence until the years before the Civil War, when Southern grand juries were quick, and Northern juries slow, to indict for crimes related to the abolition of slavery. Id. at 285-86. In almost every case in which a grand jury seemed to show independence by refusing to indict, however, the defendant was eventually indicted by a different grand jury, and in most cases the refusal to indict was based on local political reasons. Id. at 287.
The early examples of grand jury independence have not been echoed in present times. Commentators are unanimous that “in modern times the grand jury has lost much of its independent force.” 24 MOORE’S FEDERAL PRACTICE § 606.02[1]; see, e.g., Wright and Miller, FEDERAL PRACTICE AND PROCEDURE (2002) § 101, at 298 (“it is ... a mistake to overstate the extent to which a grand jury is independent” from court and prosecutor); Susan W. Brenner, The Voice of the Community: A Case for Grand Jury Independence, 3 VA. J. SOC. POL’Y & LAW 67 (1995) (documenting diminishment of grand jury’s investigative powers and arguing Supreme Court should declare procedures open to expose the lack of independence); Roger Roots, If It’s Not A Runaway, It’s Not a Real Grand Jury, 33 CREIGHTON L. REV. 821 (2000) (grand juries rarely challenge federal prosecutors and “there is no such thing as modern grand jury independence” since Federal Rules of Criminal Procedure were enacted in 1946). The lost independence includes the erosion of the grand jury’s early investigative powers, its inability to make its own presentments, and the limited nature of the grand jury's inquiry.5 This lack of autonomy is not due to the charge to the grand jury, and would not be cured by a change in the language.
The history of independence of the grand jury as an indicting body is mixed. Refusals to indict have almost always been as much political as principled. While we may want the grand jury to refuse to *1163indict when an oppressive government is unfairly targeting an individual, or when the laws being enforced are clearly (at least in retrospect) unjust, grand juries lose any guarantee of fairness if they have unfettered discretion to decide whether clear evidence of probable cause should be disregarded in each individual case. Grand juries may have any number of motivations not to issue an indictment when there is probable cause, other than the protection of the individual from an overweening government. It would be impossible to tell whether the motivation not to indict was, for example, based on local politics, racial or other discrimination, or anti-government sentiment, because grand juries operate in secret, and a decision not to indict is almost never reviewable. See Gaither, 413 F.2d at 1066; Leipold, 80 CORNELL L. REV. at 309-10.
Neither the appellants nor the dissent proposes specific language to replace the current charge. This failure is understandable, because any alternate language is fraught with problems. If, as the dissent first suggests, the grand jury were charged consistent with Vasquez, presumably with the dictum that “the grand jury is not bound to indict in every case where a conviction can be obtained,” that raises far more questions than it answers. Any grand jurors listening to the charge would wonder what that means; they have just been told to find probable cause before indicting, and they are then told that they do not have to indict if they find probable cause, without any further guidance. The dissent’s second suggestion is that the jurors be told that they must find probable cause before indicting. That is, essentially, what the current charge does. The third suggestion is that the jurors be told that they must find probable cause, but it is not the only consideration. What are the additional considerations? The dissent is silent. The difficulty in finding alternative language that does not do considerable mischief is a sign of the impracticality of giving the grand jury a charge that it has the discretion to decide, willy-nilly, whether or not to indict when there is ample probable cause.6
Further, the immediate fallout of declaring the charge unconstitutional would be sweeping. Every indictment issued by a federal grand jury given the standard charge would violate the Constitution. The dissent’s conclusion that the charge is structural error would require us to reverse every conviction in an active case reached on any indictment by a grand jury given the standard charge, dismiss the indictments, and require reindictments. This would likely apply to every criminal conviction in this circuit, as we have no indication that the standard charge generally has not been given to federal grand juries here (or across the nation).
That extreme result is unnecessary. The current charge to the grand jury informed the grand jurors that they were not merely an arm of the government, but rather an independent body.7 For instance, the grand jurors were told that:
*1164As members of the Grand Jury, you in a very real sense stand between the government and the accused. It is your duty to see to it that indictments are returned only against those whom you find probable cause to believe are guilty and to see to it that the innocent are not compelled to go to trial.
It is extremely important for you to realize that under the United States Constitution, the Grand Jury is independent of the United States Attorney and is not the arm or agent of ... any governmental agency charged with prosecuting a crime ... you must depend on your own independent judgment, never becoming an arm of the United States Attorney’s Office. If the facts suggest that you should not indict, then you should not do so even in the face of the opposition or statements of the United States Attorney.
The charge, by telling the jury that it “should” rather than “shall” or “must” indict if it finds probable cause, leaves room — albeit limited room — for a grand jury to reject an indictment that, although supported by probable cause, is based on governmental passion, prejudice, or injustice. The difference between “should” and “shall” is not, as the dissent suggests, a lawyer’s distinction, but a commonplace understanding; “shall” is used to “express what is mandatory,” “should” to express “what is probable or expected.” Webster’s Third Int’l Dictionary 2085, 2104 (1986). If a grand jury were to refuse to indict a defendant under those extreme circumstances of governmental overreaching, the charge to the grand jury would not be violated.
Meanwhile, this charge to the grand jury is consistent with the historical function of the grand jury — protecting citizens from unfounded accusations not supported by probable cause. As the Supreme Court recently stated, “the Fifth Amendment grand jury right serves a vital function in providing for a body of citizens that acts as a check on prosecutorial power.” United States v. Cotton, — U.S. -, 122 S.Ct. 1781, 152 L.Ed.2d 860 (2002) (citing 3 STORY, COMMENTARIES ON THE CONSTITUTION § 1779 (1883), reprinted in 5 THE FOUNDERS’ CONSTITUTION 295 (P. Kurland & R. Lerner eds. 1987)). Story described the grand jury’s function:
[A]n indictment is usually in the first instance framed by the officers of the government, and laid before the grand jury. When the grand jury have heard the evidence, if they are of opinion, that the indictment is groundless, or not supported by evidence, they used formerly to endorse on the back of the bill, “ignoramus” or we know nothing of it, whence the bill was said to be ignored. But now they assert in plain English, “not a true bill,” or which is a better way, “not found;” and then the party is entitled to be discharged, if in custody, without further answer. But a fresh bill may be preferred against him by another grand jury. If the grand jury are satisfied of the truth of the accusation, then they write on the back of the bill, “a true bill,” (or anciently, “billa vera.”) The bill is then said to be found, and is publicly returned into court; the party stands indicted, and may then be required to answer the matters charged against him.
From this summary statement it is obvious, that the grand jury perform most important public functions; and are a great security to the citizens against vindictive prosecutions, either by the government, or by political partisans, or by private enemies.
We conclude that the charge to the grand jury was not unconstitutional. Because there was no error in the charge, it is unnecessary to inquire further into wheth*1165er the charge constituted structural or harmless error.
APPRENDI ISSUES IN GAMBOA AND LEYVA
Gamboa and Leyva argue that the drug statutes8 under which they were convicted were facially unconstitutional after Apprendi v. New Jersey, 530 U.S. 466, 120 S.Ct. 2348, 147 L.Ed.2d 435 (2000). We have squarely rejected that argument. See United States v. Mendoza-Paz, 286 F.3d 1104, 1110 (9th Cir.2002) (21 U.S.C. § 960); United States v. Varela-Rivera, 279 F.3d 1174, 1175 n. 1 (9th Cir.2002) (21 U.S.C. § 1952). They also argue in the alternative that Apprendi would require a showing of mens rea as to drug type and quantity. We have rejected that argument as well. See United States v. Carranza, 289 F.3d 634, 644 (9th Cir.2002).
PROSECUTORIAL COMMENT IN MARCUCCI
Because Marcucci’s counsel objected to the prosecutor’s closing argument, we review to determine whether there was error, and if such error existed, whether it was harmless.
In order to evaluate whether any impropriety occurred in the prosecutor’s comments at close, it is worth considering first how Marcucci’s lawyer painted his client as too much the naif to be someone who would try to accomplish a bank robbery through intimidation. At closing, the defense argued to the jury:
To look at him and to judge him as other bank robbers is insulting to other bank robbers. I mean, this is the man that you’re going to categorize with your John Dillingers of the world? This is our sophisticate? This is- the person we’re worried about? Because if there is something in your mind going, you know what, this isn’t what I thought of when I thought of a bank robbery, this isn’t what I was expecting when I had to go to federal court, well, then your thought, that little seed in your mind is telling you the truth, which is this is not a bank robber. He did something stupid. And yeah, he would have taken the money. But was he willing to use force and violence? They are not charging him with stealing. They are not charging him with going in the bank and trying to get money that didn’t belong to him. They are saying that he did it with force and violence, and that’s a radically different thing. He was incapable of getting the money by force and violence — incapable. And the teller knew it. And that’s why she said, you know, I need approval.
To this “Marcucci does not look like a bank robber” argument, the prosecutor responded in closing by saying that just because someone doesn’t look like a threat does not mean that he is not a criminal. The prosecutor addressed the jury:
[W]hen you came in here, I suppose you had a pre-conceived notion as to how people should look, how they should behave. When you thought of a person that was shooting up a school, when you thought[of a person] that was bombing a federal building,9 did you have the preconceived notion as to what that person would look like? Sure. Everyone wants to have that. You want to have a person that makes it convenient to comply with this thought, that that person has to be the most evil looking of persons, with horns, with tails, with swastika tattoos, with little teardrops in their eyes, with *1166slicked back hair, with knuckle braces and guns and weapons blazing.... Ladies and gentlemen, those people are not all criminals, as well as those people that are criminals that commit bank robberies, that commit attempted bank robberies, are not always obvious to see.
Marcucci argues that the prosecutor committed misconduct by “comparing Mr. Marcucci to mass murderers and other infamous characters.” But, as is evident from the excerpt above, at no time did the prosecutor compare Mr. Marcucci to “school shooters and terrorists.” Rather, the prosecutor pointed out that people have preconceived notions of what criminals look like and don’t look like, and that these notions need to be and are challenged by the realities of the wide cosmetic array of criminals.
Further, the prosecutor’s “you can’t judge a book by its cover” argument falls squarely within the protected “invited reply” rule. See United States v. Young, 470 U.S. 1, 12-13, 105 S.Ct. 1038, 84 L.Ed.2d 1 (1985). While it is true that invited reply does not give a prosecutor carte blanche to engage in improper tactics, see United States v. Sarkisian, 197 F.3d 966, 990 (9th Cir.1999), this qualification does not apply to these facts. Notwithstanding Marcucci’s protestations that the prosecutor’s comments were “highly inflammatory and prejudicial,” there is little evidentiary or legal support for such a finding.
We find no evidence of prosecutorial misconduct here, and so we need not address whether such error was harmless.
CONCLUSION
The district court’s judgment is AFFIRMED.
. See 1 Sara Sun Beale et al., GRAND JURY LAW AND PRACTICE § 4:5 (2d ed.2001).
. Before Gamboa's and Leyva’s grand jury, the two Assistant U.S. Attorneys working with the grand jury were later introduced as "two wonderful public servants [who] are here to assist you in the discharge of your duties.” This praise was not mentioned before Mar-cucci's grand jury panel.
. The full text of the relevant portion of the Fifth Amendment is: "No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger ...." U.S. CONST, amend. V. “Infamous” crimes refers to at least all felonies. Cf. Stirone v. United States, 361 U.S. 212, 215, 80 S.Ct. 270, 4 L.Ed.2d 252 (1960).
. None of the additional cases cited by the dissent presented the issue of the grand jury's power to refuse to indict even where probable cause exists. The quoted portions of those cases are weak support for appellants’ argument. The quotation from Gaither v. United States, 413 F.2d 1061, 1066 n. 6 (D.C.Cir.1969), quotes language from a long-superseded 1968 version of Moore’s Federal Practice, the current version of which makes no explicit reference to any power to refuse to indict. See 24 JAMES WM. MOORE ET AL., MOORE’S FEDERAL PRACTICE § 606.02[1] (3d ed. 2002) (“Still, the grand jury can reflect the conscience of the community in providing relief when strict application of the law would prove unduly harsh.”). The dissent also quotes a concurrence in United States v. Cox, 342 F.2d 167, 189-90 (5th Cir.1965), which has no force even as Fifth Circuit precedent. The majority opinion in Cox held that a federal prosecutor could not be compelled to sign a Mississippi grand jury’s indictment for perjury against two black men in a voting rights case during the struggle for civil rights. Like Vasquez, Cox contained an inference of racial discrimination by the grand jury, "[t]he only example the Court gave where such a presumption [of fundamental unfairness in the grand jury proceeding] would exist.” 24 MOORE'S FEDERAL PRACTICE § 606.05(1]. '
Finally, none of the cases cited above deals with the charge to the grand jury. There is no indication, and the dissent does not claim, that any charge, standard or otherwise, has ever informed the grand jury that it is free not to indict even if probable cause exists.
. The Supreme Court has, over time, determined the kind or amount of information required to be disclosed to grand jurors. See, e.g., Williams, 504 U.S. at 54-55, 112 S.Ct. 1735 (grand jury need not be presented with exculpatory evidence); Costello v. United States, 350 U.S. 359, 363-64, 76 S.Ct. 406, 100 L.Ed. 397 (1956) (hearsay evidence may be sufficient basis for indictment); United States v. Calandra, 414 U.S. 338, 349-52, 94 S.Ct. 613, 38 L.Ed.2d 561 (1974) (grand jury can hear evidence obtained in violation of exclusionary rule).
. The dissent hypothesizes that in these cases the grand jury might have refused to indict the appellants because Leyva was young, the drug in Leyva’s and Gamboa's cases was only marijuana, and Marcucci was a bungling bank robber. First, because the transcripts are secret, there is no way to tell whether the grand jury knew of Leyva’s age or Marcucci's ineptness. Second, these factors should not be taken into account in a decision to indict, but at sentencing if the Sentencing Guidelines allow.
. Appellants also complain that the charge impermissibly favors the government. In light of the charge’s emphasis on the independence of the grand jury, however, the charge does not unfairly tilt the balance.
. Leyva and Gamboa were each convicted on one count of importation of marijuana under 21 U.S.C. §§ 952 and 960.
. At this point, counsel for Marcucci objected twice and was overruled by the district court. The quotation above omits the interruption of the objection and overruling.