President Lyndon B. Johnson knew the legislation he was about to sign was momentous, one that took courage for certain members of Congress to pass since the vote could cost them their seats.

To honor that, he took the unusual step of leaving the Oval Office and going to Capitol Hill for the signing ceremony. It was Aug. 6, 1965, five months after the "Bloody Sunday" attack on civil rights marchers in Selma, Alabama, gave momentum to the bill that became known as the Voting Rights Act.

In the six decades since, it became one of the most consequential laws in the nation's history, preventing discrimination against minorities at the ballot box and helping to elect thousands of Black and Hispanic representatives at all levels of government.

On Wednesday, the U.S. Supreme Court knocked out a major pillar of the law that had protected against racial discrimination in voting and representation. It was a decision that came more than a decade after the court undermined another key tenet of the law and led to restrictive voting laws in a number of states.

Voting and civil rights advocates were left fearful of what lies ahead for minority communities. "It means that you have entire communities that can go without having representation," said Cliff Albright, a co-founder of the group Black Voters Matter. "It is literally throwing us back to the Jim Crow era unapologetically, and that's not exaggeration."

Kareem Crayton, vice president of the Brennan Center for Justice's Washington office, said the court's steady work to erode the Voting Rights Act, culminating in Wednesday's decision, amounted to "burying it without the funeral."

The Supreme Court's ruling came in a congressional redistricting case out of Louisiana after the state created a district that gave the state its second Black representative to Congress.

It found that map to be an unconstitutional gerrymander because it took race into account to draw the lines. In an opinion written by Justice Samuel Alito, the court's conservative majority said the provision of the Voting Rights Act in question, called Section 2, was designed to protect voters from intentional discrimination.