Senate Majority Leader Harry Reid (D-Nev.) has filed an amicus brief with the Supreme Court backing up Attorney General Eric Holder in a voting rights case.

Shelby County, Alabama v. Eric Holder, Jr., Attorney General of the United States questions the constitutionality of Congress’ 2006 reauthorization of the Voting Rights Act, saying the body exceeded its authority under the Fourteenth and Fifteenth Amendments and thus violated the Tenth Amendment and Article IV of the Constitution.

Arguments before the high court are set for the end of this month.

“Voting is the most fundamental of our rights as Americans, and the Voting Rights Act is one of the most important laws Congress has ever passed. The Voting Rights Act, and in particular Section 5 of the law, provides crucial protection for minority voters living in jurisdictions with a history of racial discrimination. This law was reauthorized in 2006 and passed the U.S. Senate by a vote of 98-0, based on an extensive legislative record,” Reid said in a statement Friday after filing his brief.

“Congress recognized that unfortunately bigotry still exists in this nation, and that there are still those who would seek to suppress the vote on the basis of race. Indeed, during the 2012 election cycle, insidious efforts were made in various states to suppress voter turnout in minority communities.”

Section 5 requires preclearance by the Department of Justice of any attempt to change “any voting qualification or prerequisite to voting, or standard, practice, or procedure with respect to voting…” in any “covered jurisdiction,” with an eye to ensuring voting changes don’t discriminate.

“Today, I filed an amicus brief with United States Supreme Court to make clear my belief that Section 5 is not only constitutional, but a critical tool in upholding the promise of the Fourteenth and Fifteenth Amendments to the U.S. Constitution. Although our nation has made great progress in fighting prejudice and discrimination, the recent election demonstrates that Section 5 remains necessary to ensure that every eligible voter has the right to cast a ballot,” Reid said.

“If the Supreme Court dismantles this historic civil rights law and overrules the considered judgment of the people’s elected representatives, it will be a tremendous step backwards for freedom and equality in this country. I urge the Court to respect Congress’s judgment concerning what is necessary to prevent racial discrimination in election practices, and to uphold Section 5 of the Voting Rights Act.”