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This case and Commissioner v. "Americans United" Inc., post, p. 752, involve the application of the Anti-Injunction Act, § 7421...its enactment in 1867, the Anti-Injunction Act, now Code § 7421(a), provides in pertinent part that "no suit for the purpose of restraining the assessment or collection of any tax shall be maintained...liability hold property liens that compete with federal tax liens. Due to the literal meaning of the Anti-Injunction Act, such persons were, prior to 1966, often unable to protect their legitimate...