WASHINGTON — Democratic Sen. Joe Manchin was unswayed Tuesday by civil rights leaders who implored him to rethink his opposition to a sprawling election bill that House Speaker Nancy Pelosi said is crucial to countering a “Republican assault on our democracy.”

Manchin, from deeply Republican West Virginia, told reporters, “I don't think anybody changed positions,” in a meeting he described as “excellent.” A participant said Manchin was “fairly well dug in.”

The bill, known as HR1, is a top priority for Democrats and is viewed by many in the party as the antidote to a wave of Republican-backed laws being passed on the state level that restrict people's ability to vote. It touches on almost every aspect of voting and was already passed by the House.

But Manchin threw a wrench into the works Sunday when he said he would oppose the bill. That effectively dooms the measure in a narrowly divided Senate where it is universally opposed by Republicans.

His decision sent voting rights groups and members of his own party scrambling for options, raising the prospect that no voting legislation would pass Congress to address what experts say is the greatest attack on voting rights in generation.