The Supreme Court’s Shelby County v. Holder decision on Tuesday essentially cast aside the key component of the nation’s most important civil rights legislation.

The five “conservative” justices castigated Congress for putting too much emphasis on history by failing to update the “coverage formula” in Section 4 of the landmark Voting Rights Act of 1965.

Section 4 specifies which states and local jurisdictions must “pre-clear” with the Justice Department or the Washington district court all changes in election laws – anything from adding voter ID regulations to redistricting. Areas now subject to this federal oversight have had a substantial history of voter discrimination.

Chief Justice John Roberts, in writing for the 5-4 majority, conceded that the Voting Rights Act is largely responsible for a decline in blatant voting racial discrimination efforts. Yet he declared the federal oversight program “unconstitutional” on the grounds that it did not reflect “current conditions.” Instead, he invited this most dysfunctional of Congresses to “draft another formula.”

But the chief justice is wrong.

Congress did not update the formula because it knows it still works. The comprehensive database that I assembled proves this. Consider, from 1957 through 2006, almost 94 percent of all voting rights minority lawsuits, legal objections and out-of-court settlements occurred in jurisdictions now subject to federal oversight under the Section 4 formula.