CNN  — 

Senate Democrats suffered a loss on Tuesday when Republican opposition sunk their signature voting and election bill during a key test vote, underscoring the limits of the party’s power with the narrowest possible Senate majority.

A procedural vote to open debate on the legislation was defeated by a tally of 50-50, falling short of the 60 votes needed to succeed. Democrats were united in favor of the vote after securing support from Sen. Joe Manchin of West Virginia, but Republicans were united against it, causing the measure to fail to advance.

Democratic senators have pitched the legislation a necessary counter to state-level efforts to restrict voting access, but Republicans have decried it as a partisan power grab and a federal overreach into state voting and election systems.

The bill’s failure to move forward will force Democrats to confront the question of what else they can do to press the issue and will likely trigger a fresh outpouring of calls from progressives to eliminate the legislative filibuster, which requires most bills to get the votes of at least 10 Republicans given the current Senate makeup. The votes are not there, however, to eliminate the filibuster with Manchin and several other moderate Democrats opposed.

Senate Democrats are already beginning to map out their next steps to draw attention to the issue and to put the focus on a critical battleground state: Georgia.

The Democratic-led Senate Rules Committee plans to move ahead with a series of hearings, including in Georgia, calling for passage of new legislation – as well as to spotlight Republican-led efforts at the state level to enact restrictive measures in the wake of the growth of mail-in voting during the 2020 election season.

The effort by Democrats to pass the voting legislation comes in the aftermath of former President Donald Trump’s “Big Lie” that the 2020 presidential election was stolen and as Republican-controlled legislatures have pressed ahead with new state laws imposing limits on voting. As of May, state legislators in 48 states had introduced more than 380 bills with restrictive voting provisions, according to a tally from the Brennan Center for Justice at New York University.

The Senate took up an amended version of legislation that passed the House in March.

LIVE UPDATES: Senate to vote on sweeping voting rights bill

Senate Democrats had been working in recent days to try to win over Manchin, who had previously expressed concerns over the legislation.

In a statement on Tuesday ahead of the vote, Manchin said that he had “found common ground with my Democratic colleagues on a new version of the bill that ensures our elections are fair, accessible and secure,” and that as a result he will “vote ‘YES’ to move to debate this updated voting legislation.”

Senate Majority Leader Chuck Schumer told reporters that he and Manchin had reached an agreement to move ahead with the bill. “I have committed to him that if our Republican colleagues don’t obstruct and allow us to move forward on the debate, we will take up his proposed substitute amendment as the first amendment we will consider,” Schumer said.

Manchin said earlier this month that he would vote against the bill, arguing that any major legislation related to voting and elections must have bipartisan support. But he later left open the option that he could support a modified bill. The West Virginia Democrat released a proposal that would make Election Day a holiday, ban partisan gerrymandering, mandate at least 15 consecutive days of early voting and institute a voter ID requirement, among other provisions.

Schumer gave an impassioned speech on the Senate floor Monday on the significance of voting rights ahead of Tuesday’s “crucial vote” on legislation to “protect Americans’ voting rights,” which he argued “are under assault from one end of the country to the other.”

Still, Senate Minority Leader Mitch McConnell made clear on Monday afternoon that the legislation was destined to fail in the Senate, promising they would give it “no quarter.”

McConnell accused Democrats of trying to make election laws benefit their party, saying, “They’ve made it abundantly clear that the real driving force behind S1 is a desire to rig the rules of American elections permanently, permanently in Democrats’ favor,” rather than protecting the rights of voters.

McConnell previously threw cold water on Manchin’s proposal and indicated that he did not believe any Republican in the Senate would vote for it.

“There’s now a debate among Democrats over a revised version produced by one of the Democrats, ” McConnell said, before going on to call the proposal, “Equally unacceptable. Totally inappropriate.”

“All Republicans, I think, will oppose that as well,” he said.

The legislative package that passed the House calls for far-reaching ethics and government changes that would impact Congress, the president and even the Supreme Court.

It would institute an ethics code for the US Supreme Court that would apply to justices and would implement measures intended to prevent presidential conflicts of interest.

It would stop lawmakers from using taxpayer money to reach settlements in employment discrimination cases stemming from their own actions.

The bill also takes aim at Citizens United, the landmark 2010 Supreme Court decision, by calling for a constitutional amendment to overturn the ruling, which opened the door to unlimited spending by corporations and unions to influence elections.

This story and headline have been updated with additional developments Tuesday.

CNN’s Manu Raju, Ted Barrett, Ali Zaslav, Morgan Rimmer and Fredreka Schouten contributed to this report.