The Supreme Court’s decision in “Shelby County v. Holder” abandons constitutional protection of the right to vote.

The most basic requirement of any Supreme Court decision involving the application of the Constitution is to explain how the Constitution’s text and meaning command the result the Court reaches. By that standard, today’s 5-4 opinion in Shelby County v. Holder is a colossal failure. In the majority opinion by Chief Justice Roberts, the Court struck down a core provision of the Voting Rights Act – a statute that has ensured protection of the right to vote for millions of Americans – without ever explaining what provision of the Constitution rendered this iconic, landmark statute unconstitutional.

Not only that, but Chief Justice Roberts also studiously avoided the part of the Constitution most directly applicable. The Roberts opinion flouted the text and history of the Fifteenth Amendment, which expressly give to Congress broad powers to prevent and deter all forms of racial discrimination in voting.

As Justice Ruth Bader Ginsburg demonstrated in a brilliant dissent, the Fifteenth Amendment had a “transformative effect,” giving to Congress sweeping new powers to “shield the right to vote from racial discrimination.” The Fifteenth Amendment, she explained, was one of three Civil War Amendments that “arm Congress with the power and authority to protect all persons within the Nation from violations of their rights by the States.” Under the Fifteenth Amendment, Congress has the power to enact prophylactic laws, such as the Voting Rights Act, to protect the right to vote against state-sponsored racial discrimination. Justice Ginsburg gave a command performance, showing how the majority’s reasoning cannot be squared with the Constitution’s text, history, and meaning. Chief Justice Roberts had no real answer.

Conservatives like to make fun of decisions that abandon the Constitution in favor of penumbras and emanations, but that is all Chief Justice Roberts offered in today’s ruling. He argued that the Voting Rights Act is inconsistent with the “letter and spirit of the Constitution,” but his opinion is all spirit.

He placed heavy reliance on principles of state sovereignty, forgetting that the American people added the Fifteenth Amendment to make sure that Congress could act to prevent racial discrimination in voting by the states and ensure that the right to vote was a reality for all Americans regardless of race. At its most fundamental level, Shelby County is an abandonment of the Constitution’s protection of the right to vote, one of our most cherished rights.

David Gans is director of the Human Rights, Civil Rights and Citizenship Program at the Constitutional Accountability Center.