Appellee American Friends Service Committee (employer) is a religious corporation, whose principal operation is philanthropic work and many of whose employees are conscientious objectors to war, performing alternative civilian service. Appellees Lorraine Cleveland and Leonard Cadwallader (employees) are present or past employees of the employer.
Because of their religious beliefs, the employees in 1969 requested their employer to cease withholding 51.6% 1 *8of the portion of their wages required to be withheld under § 3402 of the Internal Revenue Code.2 Although they conceded that these amounts were legally due to the Government, they wished to bear witness to their beliefs by reporting the amounts as taxes owed on their annual income tax returns but refusing to pay such amounts. They would thus compel the Government to levy in order to collect the taxes.
In response to the employees’ request, the employer ceased withholding from the employees’ salaries 51.6% of that amount required to be withheld under § 3402, although it continued to pay the full amount required to be withheld under that provision to the Government. It then brought a suit for refund of the amount it had paid to the Government but not actually withheld from salaries. The appellee employees joined the employer’s action, seeking on their own behalf an injunction barring the United States’ enforcement of § 3402 against the employer with regard to 51.6% of the required withholding. They argued that, even though they were liable for these amounts, § 3402 as applied to this portion of their wages was unconstitutional as a deprivation of their right to free exercise of religion under the First Amendment since it did not allow them to bear witness to their beliefs by refusing to voluntarily pay a portion of their taxes.
The District Court ordered a refund of amounts tendered by the employer but not withheld by it, since the Government had also levied on the employees for these taxes and hence had received a double payment of the *9amount due. The Government does not contest this portion of the District Court’s judgment.3
The District Court also enjoined the United States from enforcing § 3402 against the employer with respect to 51.6% of the required withholding from the employees’ salaries, holding that § 3402 as applied to this amount constituted an unconstitutional abridgment of the right to free exercise of religion. The United States appeals this portion of the judgment.4 The District Court’s opinion and order were entered before this Court handed down its opinions in Bob Jones University v. Simon, 416 U. S. 725 (1974), and Commissioner v. “Americans United” Inc., 416 U.S. 752 (1974).
The Anti-Injunction Act, 26 U. S. C. § 7421 (a), provides that no suit for the purpose of restraining the assessment or collection of any tax shall be maintained in any court by any person, whether or not such person is the person against whom such tax was assessed.” 5 In Bob Jones, supra, we rejected an appeal to create judicial exceptions to § 7421 (a) other than that carved out in Enochs v. Williams Packing & Navigation Co., Inc., 370 U. S. 1 (1962). We noted that Williams Packing was *10the “capstone” of judicial construction of the Act and spelled an end to cyclical departures from the Act’s plain meaning. Bob Jones University v. Simon, supra, at 742. In “Americans United” Inc., supra, we stated that a pre-enforcement injunction against the assessment or collection of taxes could be granted only if it were clear that the Government could in no circumstances ultimately prevail on the merits, and that equity jurisdiction existed. “Unless both conditions are met, a suit for preventive injunctive relief must be dismissed.” 416 U. S., at 758.
The employees concede, and the District Court found, that § 3402 withholding is a method of collection of taxes within the meaning of § 7421 (a).6 They further concede, as they must, that they are not within the Williams Packing exception; far from the Government’s defense in a refund suit being meritless, the employees concede that the Government would undoubtedly prevail in such a refund action.
They contend, however, that since the District Court enjoined only one method of collection, and the Government is still free to assess and levy their taxes when due, the Act does not apply. But this contention ignores the plain wording of the Act which proscribes any “suit for the purpose of restraining the assessment or collection of any tax.” The District Court’s injunction against the collection of the tax by withholding enjoins the collection of the tax, and is therefore contrary to the express language of the Anti-Injunction Act.
*11The employees also argue that the Anti-Injunction Act is inapplicable because they have no alternative legal remedy available. They contend that a refund suit would be an inadequate remedy, in view of the concession on their part that the taxes are due, since they would surely lose such an action. But this ignores the fact that inadequacy of available remedies goes only to the existence of irreparable injury, an essential prerequisite for traditional equity jurisdiction, but only one of the two parts of the Williams Packing test. Commissioner v. “Americans United” Inc., supra, at 762; Bob Jones University v. Simon, supra, at 745. Here as in “Americans United” Inc., supra, the employees will have a “full opportunity to litigate” their tax liability in a refund suit. 416 U. S., at 762. Even though the remitting of the employees to a refund action may frustrate their chosen method of bearing witness to their religious convictions, a chosen method which they insist is constitutionally protected, the bar of the Anti-Injunction Act is not removed:
“[Decisions of this Court make it unmistakably clear that the constitutional nature of a taxpayer’s claim, as distinct from its probability of success, is of no consequence under the Anti-Injunction Act.” Id., at 759.
See also Lockerty v. Phillips, 319 U. S. 182, 187 (1943).
In Bob Jones we left open the question of whether in-junctive relief as to future collection would be proper as a form of ancillary relief in a refund suit where the taxpayer prevailed on the merits, in order to avoid the necessity of continuous subsequent “backward-looking refund suits.” 416 U. S., at 748 n. 22. That situation is not presented here since the employees have never brought a refund action, much less prevailed on the merits of such an action. Their joinder in the employer’s successful refund action, based on the receipt of double payment by *12the Government, would afford no basis for injunctive relief based on their constitutional claim. The injunctive relief granted by the District Court in this case is plainly at odds with the dual objectives of the Act: efficient and expeditious collection of taxes with “a minimum of pre-enforcement judicial interference,” and protection of the collector from litigation pending a refund suit. Bob Jones, supra, at 736-7377
The judgment of the District Court is reversed insofar as it enjoins the collection of taxes by the Government and the withholding of wages by the employer.
Reversed in part.
This figure represents their estimate of the percentage of the federal budget which is military related.
26 U. S. C. § 3402. The provision provides in part that “[e'Jvery employer making payment of wages shall deduct and withhold upon such wages (except as otherwise provided in this section) a tax determined in accordance with the following tables. . . .” There is no dispute as to the applicability of the provision to the employees’ wages.
Jurisdictional Statement 7 n. 3. We express no opinion as to the merits of the refund claim. The lower court’s opinion is reported at 368 F. Supp. 1176.
Since the District Court held that § 3402 was unconstitutional as applied to the facts of this ease, this Court has jurisdiction over the appeal under 28 U. S. C. § 1252. Fleming v. Rhodes, 331 U. S. 100, 102-103 (1947); United States v. Christian Echoes Ministry, 404 U. S. 561, 563 (1972).
See Act of Mar. 2, 1867, § 10, 14 Stat. 475; Rev. Stat. §3224; Int. Rev. Code of 1939 § 3653. Section 7421 (a) of the Code states: “Except as provided in sections 6212 (a) and (c), 6213 (a), and 7426 (a) and (b)(1), no suit for the purpose of restraining the assessment or collection of any tax shall be maintained in any court by any person, whether or not such person is the person against whom such tax was assessed.”
The legislative history of this provision enacted in 1943 indicates that its purpose in part was to assist the Government in securing needed revenue without having to resort to levy. H. R. Rep. No. 268, 78th Cong., 1st Sess., 1-2 (1943); S. Rep. No. 221, 78th Cong., 1st Sess., 1 (1943). The District Court noted that relegating the Government to levying after returns were filed would be an inefficient process. 368 F. Supp., at 1180.
Because we have concluded that the Anti-Injunction Act bars injunctive relief, we have not found it necessary to decide other threshold issues such as whether a three-judge District Court was required, whether the sovereign immunity of the United States barred the suit, and whether the requirements of 28 U. S. C. § 1331 were met.