Atlanta (AFP) - President Joe Biden took a major political gamble Tuesday in calling for a break in the Senate's supermajority rule so that Democrats can override Republican opposition to voting rights reforms that he called crucial to saving US democracy.

Speaking in Atlanta, Georgia, the cradle of the civil rights movement, Biden -- who called last year's Capitol riot by Donald Trump supporters an "attempted coup" -- declared "this is the moment to decide to defend our elections, to defend our democracy."

He challenged Democrats holding a razor-thin majority in the Senate to stand up for two bills that would expand access to polls and prevent practices that Biden said are being used to suppress Black and other Democratic-leaning voters.

"Each one of the members of the Senate will be judged by history for where they stood before the vote and after the vote. There's no escape," Biden said.

The 50 Democrats in the Senate support the two bills. However, under current the supermajority requirement, 60 votes are needed to get them passed.

Biden said that if Republicans don't cooperate then the supermajority requirement, called the filibuster, should be tossed to get the voting rights acts through.

Facing Republican obstruction, "we have no option but to change the Senate rules including getting rid of the filibuster for this."

It's a high-risk, high-gain issue for Biden, who is infuriating Republicans, while also trying to balance the more conservative wing of his party with the increasingly frustrated Black community.

History is watching

Coming off a powerful speech last week marking the January 6 anniversary of the pro-Trump riot, Biden described the push to enshrine greater voter protections as "a turning point." 

Democrats accuse Republican state legislatures of enacting a spate of laws deliberately restricting the voting rights of minorities and curtailing early voting and mail-in voting in an effort to suppress Democratic support.

Biden said Republicans are passing local laws "designed to suppress your vote, to subvert our elections."

Then throwing down the gauntlet to the Senate, Biden said: "History has never been kind to those who sided with voter suppression over voter rights."

"I ask every elected official in America: how do you want to be remembered?"

Political risk

Republicans describe the Democrats' Senate push for voting rights as an attempt to manipulate the election landscape by switching power to federal authorities. They are unanimous in opposing the two bills, which Senate Majority Leader Chuck Schumer said could come up for a vote as early as Wednesday.

Biden's bid for a suspension of the filibuster rule is also controversial.

Republicans warn that a supposedly one-off maneuver could open the floodgates to lifting the filibuster on all sorts of issues, thereby ending any semblance of bipartisanship in the chamber.

Lead Republican Senator Mitch McConnell called the idea of suspending the filibuster for voting rights reforms "disturbing" and an attempt to "break our institutions to get a political outcome they want."

Perhaps worse for Biden, the maneuver needs unanimous Democratic support to happen -- and that's far from assured, with at least two of the more conservative Democratic senators clearly skeptical.

If circumventing the filibuster fails, Biden will not only see the voting rights bills defeated but emerge from the fight looking politically weakened.

'Keep the faith'

The president traveled to Georgia at a time when his approval ratings are stuck in the low 40s and Republicans are predicted to take over Congress in November midterm elections.

He not only faces ferocious pushback from Republicans on his voter rights initiative, but complaints from Black activists -- a crucial part of his coalition -- that he has done too little, too late.

Underlining Biden's shaky political standing, prominent Black politician and Georgia voting rights activist Stacey Abrams missed his Atlanta event due to what Biden called a "scheduling" glitch, while a big civil rights group said it was boycotting due to lack of tangible progress.

Still, the speech was the boldest step yet into the issue by Biden, who attended a wreath laying at the crypt of slain civil rights icon Martin Luther King Jr and visited the historic Ebenezer Baptist Church ahead of his speech.

"Keep the faith," Biden said as he entered the Ebenezer Baptist church.