Cite as: 570 U. S. ____ (2013) 19 Opinion of the Court The Government suggests that Katzenbach sanctioned such an approach, but the analysis in Katzenbach was quite different. Katzenbach reasoned that the coverage formula was rational because the “formula . . . was relevant to the problem”: “Tests and devices are relevant to voting discrimination because of their long history as a tool for perpetrating the evil; a low voting rate is pertinent for the obvious reason that widespread disenfranchisement must inevitably affect the number of actual voters.” 383 U. S., at 329, 330. Here, by contrast, the Government’s reverseengineering argument does not even attempt to demonstrate the continued relevance of the formula to the problem it targets. And in the context of a decision as significant as this one—subjecting a disfavored subset of States to “extraordinary legislation otherwise unfamiliar to our federal system,” Northwest Austin, supra, at 211—that failure to establish even relevance is fatal. The Government falls back to the argument that because the formula was relevant in 1965, its continued use is permissible so long as any discrimination remains in the States Congress identified back then—regardless of how that discrimination compares to discrimination in States unburdened by coverage. Brief for Federal Respondent 49–50. This argument does not look to “current political conditions,” Northwest Austin, supra, at 203, but instead relies on a comparison between the States in 1965. That comparison reflected the different histories of the North and South. It was in the South that slavery was upheld by law until uprooted by the Civil War, that the reign of Jim Crow denied African-Americans the most basic freedoms, and that state and local governments worked tirelessly to disenfranchise citizens on the basis of race. The Court invoked that history—rightly so—in sustaining the disparate coverage of the Voting Rights Act in 1966. See Katzenbach, supra, at 308 (“The constitutional propriety of