Page:United States Reports, Volume 542.djvu/165

126 and their administration accords with the direct, broad, and unqualified language of the statute. The Act bars all orders that enjoin, suspend, or restrain the assessment of any tax under state law. In effecting congressional intent we should give full force to simple and broad proscriptions in the statutory language.

Because the TIA's language and purpose are comprehensive, arguments based on congressional silence on the question whether the TIA applies to actions that increase moneys a state tax system collects are of no moment. Contra, Winn, 307 F. 3d, at 1017–1018 (relying on Dunn v. Carey, (CA7 1986)); see also ante, at 108–109 (relying on Dunn). Whatever weight one gives to legislative histories, silence in the legislative record is irrelevant when a plain congressional declaration exists on a matter. "[W]hen terms are unambiguous we may not speculate on probabilities of intention." Insurance Co. v. Ritchie, 5 Wall. 541, 545 (1867). Here, Congress has said district courts are barred from disrupting the State's tax operations. It is immaterial whether the State's collection is raised or lowered. A court order will thwart and replace the State's chosen tax policy if it causes either result. No authority supports the proposition that a State lacks an interest in reducing its citizens' tax burden. It is a troubling proposition for this Court to proceed on the assumption that the State's interest in limiting the tax burden on its citizens to that for which its law provides is a secondary policy, deserving of little respect from us.

The final basis on which both the majority and respondents rest is that years of unexamined habit by litigants and the courts alike have resulted in federal courts' entertaining challenges to state tax credits. See ante, at 110–111 (citing representative cases). While we should not reverse the course of our unexamined practice lightly, our obligation is to give a correct interpretation of the statute. We are not