A message for the senate to pass voting rights legislation sponsored by Democracy, is seen on 3rd Street SW, on Tuesday, January 18, 2022. (Getty Images)

US Senate Democrats have again failed to pass voting rights legislation when two senators refused to join their own party in changing Senate rules to overcome a Republican filibuster.

Senate Republicans, in back-to-back votes late on Wednesday, first blocked Democrats’ move to advance the legislation toward passage. It was the fifth time in less than a year they did so.

They employed the filibuster, a Senate rule that requires 60 votes to advance legislation to a final vote. The Senate currently is split 50-50.

Then, Senate Majority Leader Chuck Schumer, a Democrat, quickly moved to revamp the filibuster rule by lowering the 60-vote threshold to 50.

However, Schumer’s own Democrats - conservatives Joe Manchin and Kyrsten Sinema - voted against the rules change.

The vote was 52-48, with the two joining all GOP senators. After the vote failed, there was a loud round of applause from Republicans.

The voting rights legislation would expand early and mail-in voting and make Election Day a national holiday, among a bevy of other reforms.

The measure is a key issue for the party, which is under pressure to take action ahead of the midterm elections just months away.

In a statement following the votes, President Joe Biden said he is profoundly disappointed that the United States Senate has failed to stand up for our democracy.

I am disappointed - but I am not deterred, he said, adding that his administration will explore every measure and use every tool at our disposal to stand up for democracy.

All 50 senators in the Democratic caucus have backed the voting rights bills before the Senate.

Some Republicans have sounded open to reforming the process of counting electoral votes after a presidential election to make it harder to overturn a result.

The bid comes in response to efforts by former President Donald Trump and his allies who tried to reverse Biden’s 2020 presidential election victory based on false claims of widespread cheating.

After courts rejected Trump’s repeated efforts to overturn state results, his allies pressured former Vice President Mike Pence to step in when Congress counted electoral votes on Jan. 6, 2021.

Pence did not try to reverse the presidential result. But Trump’s supporters stormed the Capitol building, where lawmakers were in the process of confirming Biden’s win.

The bloody attack resulted in the deaths of at least five people, including a police officer.

Trump was impeached, for the second time, for inciting his supporters to storm the Capitol building on the opening weeks of Biden’s presidency.

The Republican president, however, was ultimately acquitted.