Liberal activists and Democratic lawmakers are angling to use a planned Senate vote Tuesday on broad legislation to overhaul election access, campaign finance and government ethics — which is expected to fail because of solid Republican opposition — as an inflection point in a major last-ditch push to change Senate rules and pass voting rights legislation before the end of the summer.

Advocates of federal intervention who have been spurred to action by the raft of new, more restrictive state voting laws passed by Republican legislatures face a steep uphill battle after Tuesday’s vote. No GOP senators are expected to vote to even begin debating legislation, and several Democratic senators have made it clear that they oppose a move that could allow further action — eliminating the 60-vote supermajority rule known as the filibuster.

But top party leaders are betting that a show of firm GOP intransigence in Tuesday afternoon’s procedural vote will prompt movement among the handful of wary Democrats. In a fiery floor speech Monday that served, in part, as a veiled appeal to members of his own caucus, Senate Majority Leader Charles E. Schumer (D-N.Y.) hammered the point that Republicans were threatening to block even a discussion of voting rights.

Senate Democrats have two options right now to strengthen voting rights: Passing the For the People Act or the John Lewis Voting Rights Act, neither is easy. (Mahlia Posey/The Washington Post)

“Will our Republicans let us debate?” he said at the close of his remarks Monday. “That’s the only question on the table for the United States Senate tomorrow, and we’re about to find out how my Republican colleagues will answer that question.”

The rhetorical point is aimed at the likes of Sen. Joe Manchin III (D-W.Va.), who was a lone holdout among Democrats in endorsing the sweeping For the People Act, which passed the House in February, and has consistently opposed eliminating the filibuster to pass any legislation on party lines. It is also aimed at a broader group of Democrats, including Sen. Kyrsten Sinema (D-Ariz.), who support the House-passed legislation but have opposed changing Senate rules to pass it. Advocacy groups, meanwhile, are preparing to launch a flurry of efforts aimed at convincing those senators to drop their objections to counter the succession of state laws, which have overwhelmingly passed on party lines. They are hoping to force the Senate to revise the filibuster and pass a voting bill before the chamber breaks for its traditional August recess, giving states time to implement it before the 2022 midterms.

“This issue is not going away — it’s only going to be increasing in pressure until they do something about it,” said Eli Zupnick, a spokesman for Fix Our Senate, a coalition of liberal groups pushing for the end of the filibuster that is launching a million-dollar ad campaign this week targeting key senators. “The way that Senate Democrats and President Biden can take this issue off the table is by dealing with it now. There’s no kicking the can on this.”

Stephen Spaulding, senior counsel with Common Cause, said Tuesday’s vote is “the first step in a concerted summer-long fight to get this bill across the finish line.”

“It’s by no means over tomorrow,” he said.

More than 70 groups launched a national “Deadline for Democracy” campaign last week to support action during the July recess. Leah Greenberg, co-executive director of the Indivisible Project, said the coalition was “pulling out all the stops” to engage thousands of advocates and plan events across nearly 30 states and Washington, including town halls and rallies outside of senators’ offices.

“The Senate Democratic Caucus has to have a hard conversation with each other and ask, ‘Are we going to allow an obscure legislative procedure that’s really just an accident of history to prevent us from accomplishing what we ran on and enacting the kind of changes that are needed to secure the American people’s right to vote?’ ” Greenberg said.

A coalition of groups has contacted 2 million voters and activists through door-knocking, phone calls, text messages and emails, including in Arizona, West Virginia and Georgia, said Adam Bozzi, spokesperson for End Citizens United/Let America Vote. His group has spent more than $17 million on paid communications via television, mail and the digital sphere as part of a $30 million spending commitment with the National Democratic Redistricting Committee, he said.

Eighteen states have enacted more than 30 laws that restrict voting, according to the nonpartisan Voting Rights Lab, which tracks developments in state election rules. The restrictions affect roughly 36 million people, or 15 percent of all eligible voters, the group stated in a report last week.

The laws restrict access to mail voting, create new hurdles to register to vote, impose new voter ID requirements and expand the definition of criminal behavior by voters, election officials and third parties, among other changes.

Republicans on Capitol Hill have firmly rejected any attempt at federal intervention. Senate Minority Leader Mitch McConnell (R-Ky.) said in his own floor speech Monday that the Democrats’ push for voting legislation should be viewed as a simple partisan power play. “They’ve made abundantly clear that the real driving force behind [the For the People Act] is the desire to rig the rules of American elections permanently, permanently, in Democrats’ favor,” he said. “That’s why the Senate will give this disastrous proposal no quarter.”

McConnell, who has warned in the past that any attempt by Democrats to unilaterally repeal the filibuster would be met by “scorched earth” tactical retribution, has rallied his own ranks behind blanket opposition to the bill. He summarily rejected last week a compromise framework extended by Manchin, who proposed accepting some aspects of the House-passed proposal, such as a guaranteed period of early voting, while rejecting others, such as systems to broadly register voters automatically.

Manchin also proposed incorporating some traditional GOP priorities into the legislation, including a national voter ID mandate, but McConnell said it was too little, too late. Manchin told reporters Monday that he was still seeking assurances from fellow Democrats that his revisions would be incorporated into the legislation and had not yet agreed to vote to start debate. If an accord is reached, it would set up a strict party-line vote Tuesday.

“I would commend them for coming around to a common sense position that 80 percent of Americans already support,” he said of voter ID. But Manchin’s proposal, he added, “bears more than a passing resemblance to the partisan power grab their party has touted for years.”

Notably, the bill was a central topic of conversation in a White House meeting Manchin had with President Biden on Monday. The president “expressed his sincere appreciation for Sen. Manchin’s efforts to achieve reform” and “made it clear how important he thinks it is that the Senate find a path forward on this issue,” an administration official said Monday, speaking on the condition of anonymity to describe the private talks. Schumer, meanwhile, challenged Republicans to defend the new state laws, accusing the GOP of engaging in a power grab of their own, having fallen in line with former president Donald Trump’s false claims of a stolen 2021 election.

“The only thing that changed between 2020 and 2021 was Donald Trump’s big lie about massive fraud,” Schumer said. “Let’s dispense with this nonsense: There is no real principle behind these policies. They are not about election integrity. They are not about voter fraud. These policies have one purpose and one purpose only: making it harder for younger, poorer, non-White and typically Democratic voters to access the ballot.”

In Arizona, voters who do not cast a ballot at least once every two years will have to respond to a government notice to avoid being removed from the list and to continue getting a ballot in the mail.

In Florida, far-reaching new restrictions mean voters will have to renew their mail voting application every two years and submit a form of identification to be approved.

And in Georgia, a wide-ranging new law means election officials are barred from proactively sending mail ballot applications to voters, among other restrictions.

While the Senate prepares to vote on whether to consider any legislation at all, some Democrats are offering further refinements to the bill. One group of lawmakers is preparing an amendment aimed at overriding “election subversion” — targeting GOP-passed state laws that could allow partisan state officials or legislatures to overrule election results.

According to an outline obtained by The Washington Post, the amendment would include measures aimed at preventing states from suspending or removing local elections official in a bid to overturn an election, as well as making it a federal crime to harass or intimidate election workers. It would also create a minimum buffer zone that partisan election observers must maintain from voters or ballots to prevent interference.

The proposal is being put forward by Democratic Reps. Colin Allred (Tex.), Zoe Lofgren (Calif.), John Sarbanes (Md.) and Nikema Williams (Ga.) and Sens. Amy Klobuchar (Minn.), Jeff Merkley (Ore.) and Raphael G. Warnock (Ga.).

But the new amendment will not be enacted into law so long as the voting rights bill remains mired in the Senate, and Democrats acknowledge that is unlikely to change so long as the filibuster remains in place.

Manchin maintained in a recent op-ed that he would never “eliminate or weaken” the filibuster, saying it is needed to encourage bipartisanship, and Sinema has offered similar defenses of the long-standing Senate rule. Several other senators have expressed varying levels of discomfort with rules changes.

But activists say they believe their minds could still be changed — and quickly.

“Nobody is asking him to reverse himself,” Zupnick said on Manchin. “Anything he would do would be strengthening the filibuster, which is clearly not working.”

White House press secretary Jen Psaki on Monday acknowledged the likely failure of Tuesday’s vote but called it a “step forward” that could ultimately produce action.

“We suspect it will prompt a new conversation about the path forward, and we’ll see where that goes,” she said in a reference to the fate of the filibuster.

Paul Kane and Seung Min Kim contributed to this report.