Appellant filed a libel in personam against the Republic of Tunisia. D.D.C. Admiralty No. 27-62. A summons was issued addressed to the Republic to be served upon the Tunisian Ambassador to the United States. Appellee, the United States Marshal, made the following return upon the unexecuted summons: “The within named principal agent having Diplomatic Immunity and being listed in the Diplomatic List of the State Department cannot be served at Washington, D. C. * * * ” Appellant then filed this mandamus action to compel appellee to serve the summons “in conformity with the dignity and respect to be accorded representatives of a foreign government.” The court granted appellee’s motion to dismiss.
The only issue is whether the Marshal’s return provided an adequate reason for his refusal to serve the summons. The return indicated that the Ambassador was entitled to diplomatic immunity. If the Ambassador’s diplomatic immunity would in fact have been violated by service of process, the Marshál’s return was sufficient. For although courts will not allow a Marshal to avoid his duty to serve process merely because he notices the availability of a defense to the suit,1 they must protect him if service would violate international law and might subject him to the criminal law of the United States.2 Since we *980think that the Ambassador’s diplomatic immunity would have been violated by any compulsory service of process on him by the Marshal,3 we conclude that the return was sufficient, and the district court’s dismissal was proper.
Although we have held that diplomatic immunity is violated by joining a diplomatic officer as a defendant to a suit, Carrera v. Carrera, 84 U.S.App.D.C. 333, 174 F.2d 496 (1949), we have never decided whether it is violated by service of process on a diplomatic officer in an attempt to join, not him, but his sending state. There is little authority in international law concerning whether service of process on a diplomatic officer as an agent of his sending country is an “attack on his person, freedom or dignity” prohibited by diplomatic immunity.4 Because application of the doctrine of diplomatic immunity exempts a person from the legal procedures necessary to ordered society and often deprives others of remedies for harm they have suffered, courts hesitate to invoke the doctrine in a novel situation unless its purposes will certainly be served. These purposes are to “contribute to the development of friendly relations among nations” and “to ensure the efficient performance of the functions of diplomatic missions.” Vienna Convention on Diplomatic Relations Signed at Vienna, April 18, 1961, preamble, 55 Am.J.Int’l.L. 1064 (1961). We requested the views of the Department of State concerning the effect of service in this type of case on international relations and on the performance of diplomatic duties. The Department replied that service would prejudice the United States foreign relations and would probably impair the performance of diplomatic functions.5 We conclude that the *981purposes of diplomatic immunity forbid service in this case.6 Therefore, the Ambassador is not subject to service of process, and the return was adequate.
The judgment is Affirmed.
. The Marshal -would not be permitted to refuse service because, for example, he notices that venue is improper, since the defendant might not wish to raise the defense. The defendant might decide that, although venue were improper, defense of the suit in the proper venue would be less convenient or would under 8rie R. R. v. Tompkins, 304 U.S. 64, 58 S.Ct. 817, 82 L. Ed. 1188, 114 A.L.R. 1487 (1938), require the application of less desirable law. Similarly, a sovereign sued in the United States might waive its immunity defense because it could more easily present its witnesses and evidence here or because the law would be more favorable here than in courts of alternative forums where it would have no immunity defense. The sovereign might also decide that an airing of the dispute in an independent judicial tribunal would further its domestic policies or its foreign relations.
. Statutes passed in 1790 make it criminal for any officer to execute any process “whereby the person of any ambassador * * * of any foreign * * * State * * * is arrested or imprisoned, or his *980goods or chattels are distrained, seized, or attached * * *.” 22 U.S.C. §§ 252, 253 (1952). These statutes are liberally-construed as being declarative of international law of diplomatic immunity. In re Baiz, 135 U.S. 403, 420, 10 S.Ct. 854, 34 L.Ed. 222 (1890); see Carrera v. Carrera, 84 U.S.App.D.C. 333, 174 F.2d 496 (1949); Bergman v. De Sieyes, 71 F. Supp. 334 (S.D.N.Y.1946).
. We do not decide whether service of process by diplomatic note would violate diplomatic immunity. In reply to our request for information, the Department of State through its Acting Legal Adviser stated, “The Department would not, in the absence of express statutory or treaty provision, attempt to transmit the summons by an official diplomatic note to the embassy of a sending state, unless the embassy indicated a willingness to accept the summons.” .Letter from Leonard C. Meeker to John W. Douglas, Assistant Attorney General, August 10, 1964.
Although an ambassador may be served if he consents to service, the failure of the Marshal to state on the return that he attempted to ascertain whether the Ambassador would accept service voluntarily did not render the return inadequate. We do not think that the Marshal should be burdened with a duty to investigate whether diplomatic immunity will be waived. Bather that burden should rest on the party seeking service.
. Article 29 of the Vienna Convention requires that “The person of a diplomatic agent shall be inviolable. He shall not be liable to any form of arrest or detention. The receiving state shall treat him with due respect and shall take all appropriate steps to prevent any attack on his person, freedom or dignity.” 55 Am. J.Int’l L. 1064, 1070-1071 (1961).
The Vienna Convention has been signed by 63 states, including the United States. It came into force on April 24, 1964, having been finally accepted by 28 states. The treaty is now before the United States Senate for its advice and consent to ratification. See Maktos, Diplomatic Immunity, 31 D.O.Bab J. 227, 231 (1964).
. On possible impairment of a diplomatic ofiicer’s performance of official duty, the State Department said, “It is quite probable that such impairment would be caused; the degree of it would depend on the circumstances. An ambassador and his government would in all likelihood consider that he had been hampered in the performance of his duties if, for example, (a) the ambassador felt obliged to restrict his movements to avoid finding himself in the presence of a process server; or (b) he were diverted from the performance of his foreign relations functions by the need to devote time and attention to ascertaining the legal consequences, if any, of service of process *981having been made, and to taking such action as might be required in the circumstances; or (c) the manner of service had been publicly embarrassing to him and called attention to the infringement of his personal inviolability.” Moreover, “The maintenance of friendly foreign relations between the United States and the sending state concerned would certainly be prejudiced by service of process on an ambassador against his will. The sending state might well protest to the Department that the United States had failed to protect the person and dignity of its official representative, and might complain particularly that service was by an officer of the United States Government, namely, a United States Marshal. Other governments might interpret the incident as meaning that the Government of the United States had decided, as a matter of policy, to depart from what they had considered a universally accepted rule of international law and practice.” Letter from Leonard 0. Meeker, Acting Legal Adviser of the Department of State, to Nathan J. Paulson, Clerk of the United States Court of Appeals for the District sof Columbia Circuit, January 13, 1965.
. “[Sjerious and far-reaching consequences would flow from a judicial finding that international law standards had been met if that determination flew in the face of a State Department proclamation to the contrary. When articulating principles of international law in its relations with other states, the Executive Branch speaks not only as an interpreter of generally accepted and traditional rules, as would the courts, but also as an advocate of standards it believes desirable for the community of nations and protective of national concerns.” Banco Nacional de Cuba v. Sabbatino, 376 U.S. 398, 432, 84 S.Ct. 923, 942, 11 L.Ed.2d 804 (1964). Our courts have deferred to the views of the State Department as to whether sovereign immunity should be granted. See National City Bank of New York v. Republic of China, 348 U.S. 356, 75 S.Ct. 423, 99 L.Ed. 389 (1955); Republic of Mexico v. Hoffman, 324 U.S. 30, 65 S.Ct. 530, 89 L.Ed. 729 (1945); Ex parte Republic of Peru, 318 U.S. 578, 63 S.Ct. 793, 87 L.Ed. 1014 (1943); Compania Española de Navegación Maritima, S.A. v. Navemar, 303 U.S. 68, 58 S.Ct. 432, 82 L.Ed. 667 (1938).