Progressive groups are ramping up pressure on Senate Democrats to nix the legislative filibuster ahead of a voting rights fight set to come to a head in a matter of weeks. 

More than 100 progressive groups, led by Fix Our Senate, are poised to send a letter to Senate Democrats on Thursday painting the fight over the legislative filibuster as a decision between siding with democracy or defending a "'Jim Crow relic.'" 

"We understand that the Senate plans to address voting rights and democracy protection as soon as it returns from recess. To meet the urgency of the moment and scale of the threat, we call on the Senate to return to Washington as quickly as possible to address the filibuster and deliver the federal voting and democracy protections we need," the groups wrote in the letter, a copy of which was obtained by The Hill. 

"There is not a moment to waste. Every day that passes with the filibuster still standing, as it does today, threatens the health of our democracy and the voting rights of our fellow Americans. The choice is crystal clear: stand with us and your constituents and protect our democracy, or protect the abused and outdated 'Jim Crow relic.' There is no third option," the groups add in the letter.

In addition to the letter, Fix Our Senate announced on Wednesday that it is extending an ad campaign, previously announced in June, to include an additional five-figure buy targeting Democrats in key states. 

“The Fix Our Senate coalition has grown to over 80 organizations representing millions of people delivering one clear message: protect our democracy, not the ‘Jim Crow’ filibuster,"  Eli Zupnick, a spokesperson for Fix Our Senate, said in a statement.  

Senate Majority Leader Charles Schumer (D-N.Y.) has teed up a fight over voting rights once the chamber returns to Washington, D.C., in mid-September. 

Schumer, at the end of an all-night session last month, teed up the vote, for which he'll need the support of at least 10 Republicans to help start debate. Absent a significant, unexpected, shift — either by Republicans on voting legislation or moderate Democrats on changing the chamber's rules — the effort is expected to fall short.  

Democrats have been working behind-the-scenes for weeks to try to figure out a scaled-down version of the For the People Act, a sweeping bill to overhaul federal elections, that could win over the support of all 50 Democrats. If they are able to reach a deal by the time the Senate returns they could then swap text of it into the bill that Schumer has teed up if they are able to start debate.  

"Voting rights, voting rights, will be the first matter of legislative business when the Senate returns to session in September. Our democracy demands no less. ...It is my intention that the first amendment to the bill would be the text of a compromise bill that a group of senators are working on," Schumer said at the time. 

But a push to get election-related legislation through the Senate faces a familiar roadblock: The 60-vote legislative filibuster. 

Senate Republicans previously blocked debate on the For the People Act, and are expected to block the Senate's debate in roughly two weeks. 

To pass voting rights through the Senate without GOP votes Democrats would need all 50 members of their caucus to agree to get rid of or pare down the legislative filibuster.  

But Sens. Kyrsten Sinema (D-Ariz.) and Joe Manchin (D-W.Va.) oppose getting rid of the filibuster, and Manchin has specifically come out against creating a carve out for voting rights legislation. Other Democrats are viewed as wary of nixing the filibuster, though advocates believe they would support doing so if Republicans repeatedly block voting legislation.  

Democrats had pointed to August as a crucial self-imposed deadline for passing voting rights legislation because the Census Bureau releases redistricting data that advocates worry will be used to muscle Democrats out of key districts heading into the midterm elections. 

Senate Democrats missed the August deadline amid an entrenched stalemate on how to get a bill to Biden's desk, sparking worry from progressives that they are running out of time.  

"Unless the Senate joins the House in passing strong federal legislation in response - and quickly - it will be too late to protect voting rights in the 2022 midterm elections and draw fair districts in the decennial redistricting process," the progressive groups warned in their letter to Senate Democrats.