Racial discrimination in voting is “one of the gravest evils that Congress can seek to redress,” Judge David Tatel wrote in a crucial ruling on Friday upholding the constitutionality of the Voting Rights Act. In extending the law in 2006, Congress did just that, after reviewing racial bias in the nine states and parts of several others that have deep histories of discrimination. These “covered jurisdictions” had long been required by Section 5 of the law to get permission from the Justice Department or a federal court before making any changes to their voting rules. Congress found that discriminatory practices were still persistent and pervasive in those jurisdictions, and that the preclearance requirement remained necessary. In his 2-to-1 majority opinion for the United States Court of Appeals for the District of Columbia, Judge Tatel explained that Congress’s judgment, supported by a legislative record of more than 15,000 pages and 22 hearings, “deserves judicial deference” because of the weight of the evidence. The ruling upheld a forceful decision by a federal district judge that reached the same conclusion in 2011.