WASHINGTON — The Supreme Court’s decision to halt efforts to create a second mostly Black congressional district in Alabama for the 2022 election sparked fresh warnings Tuesday that the court is becoming too politicized, eroding the Voting Rights Act and reviving the need for Congress to intervene.

The Supreme Court’s conservative majority put on hold a lower court ruling that Alabama must draw new congressional districts to increase Black voting power.

Civil rights groups had argued that the state, with its “sordid record” of racial discrimination, drew new maps by “packing” Black voters into one single district and “cracking” Black voters from other districts in ways that dilute their electoral power.

Black voters are 26% of Alabama’s electorate.

In its 5-4 decision Monday, the Supreme Court said it would review the case in full, a future legal showdown in the months to come that voting advocates fear could further gut the protections in the landmark Civil Rights-era law.

It’s “the latest example of the Supreme Court hacking away at the protections of the voting rights act of 1965,” said Sen. Dick Durbin, D-Ill., chairman of the Judiciary Committee.

The outcome all but ensures Alabama will continue to send mostly white Republicans to Washington after this fall’s midterm elections and applies new pressure on Congress to shore up voter protections after a broader elections bill collapsed last month. And the decision shows the growing power of the high court’s conservative majority as President Joe Biden is under his own pressures to name a liberal nominee to replace retiring Justice Stephen Breyer.

Rep. Terri Sewell, the only Black representative from Alabama, said the court’s decision underscores the need for Congress to pass her bill, the John R. Lewis Voting Rights Advancement Act, to update and ensure the law’s historic protections.

“Black Alabamians deserve nothing less,” Sewell said.

The case out of Alabama is one of the most important legal tests of the new congressional maps stemming from the 2020 census count. It comes in the aftermath of court decisions that have widely been viewed as chiseling away at race-based protections of the Voting Rights Act.

Alabama and other states with a known history of voting rights violations were no longer under federal oversight, or “preclearance,” from the Justice Department for changes to their election practices after the court, in its 2013 Shelby v. Holder decision, struck down the bill’s formula as outdated.

As states adjust their congressional districts to fit population and demographic data, Alabama’s GOP-led Legislature drew up new maps last fall that were challenged by civil rights groups on behalf of Black voters in the state.

Late last month, a three-judge lower court, which includes two judges appointed by former President Donald Trump, had ruled that the state had probably violated the federal Voting Rights Act by diluting the political power of Black voters. This finding was rooted, in part, in the fact that the state did not create a second district in which Black voters made up a majority, or close to it.

Given that more than one person in four in Alabama is Black, the plaintiffs had argued the single Black district is far less than one person, one vote. The lower court gave the Alabama legislature until Friday to come up with a remedial plan.

Late Monday, the Supreme Court, after an appeal from Alabama, issued a stay. Justices Brett Kavanaugh and Samuel Alito, part of the conservative majority, said the lower court’s order for a new map came too close to the 2022 election.

Critics went beyond assailing the decision at hand to assert that the court has become political.

“I know the court likes to say it’s not partisan, that it’s ... apolitical, but this seems to be a very political decision,” said Democratic Sen. Chris Van Hollen of Maryland.

Rep. Hakeem Jeffries, D-N.Y., tweeted that the court majority has “zero legitimacy.”

Alabama Republicans welcomed the decision.

“It is great news,” said Rep. Mo Brooks who is running for the GOP nomination for Senate. He called the lower court ruling an effort to “usurp” the decisions made by the state’s Legislature.

The justices will at some later date decide whether the map produced by the state violates the voting rights law, a case that could call into question “decades of this Court’s precedent” about Section 2 of the act, Justice Elena Kagan wrote in dissent. Section 2 prohibits racial and other discrimination in voting procedures.