US President Joe Biden Photo: VCG

President Joe Biden plunges into a historic, politically explosive battle on voting reforms Tuesday with a speech in Georgia, the heart of the US civil rights struggle.

Coming off a powerful speech last week to mark the January 6 anniversary of an attempt by Donald Trump's supporters to overturn the 2020 presidential election, Biden will argue in the state capital Atlanta that Congress needs to pass laws to protect the country's democracy.

Democrats have accused Republican state legislatures of enacting laws that would restrict the voting rights of minorities and curtail early voting and mail-in voting. 

The issue pits Democrats against Republicans in what both sides are portraying as battle over freedom itself.

And adding to the drama, Democrats' only chance to pass such reforms would be to use a Senate procedure that Republicans warn will wreck what remains of already dwindling bipartisan spirit in the divided legislature.

The president is joining the fray 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. The White House says Biden feels it's time to go big on a key Democratic ambition.

"He believes the stakes should be raised. He wouldn't be going to Georgia... if he wasn't ready," White House Press Secretary Jen Psaki said.

Democrats say there's an existential need for reforms, following the unprecedented chaos of 2020, brought on by Trump's attempt to dodge defeat.

According to Democrats, bills under consideration would prevent cheating, ranging from partisan drawing of election districts to the use of security measures as a way to dampen voter turnout in pro-Democrat districts. 

The laws would also end the potential ability of state authorities to rig results under arcane existing rules.

"We are going right to the belly of the beast, or ground zero, for voter suppression, voter subversion and obstruction," Cedric Richmond, White House senior adviser, told Politico.

Republicans are just as adamantly opposed, leaving Democrats with only the so-called "nuclear option" of ending the filibuster.

The Senate is split 50:50, with Vice President Kamala Harris coming in for the Democrats on tie breaks.

Under an unofficial, but now accepted convention, however, either side can declare a so-called filibuster, automatically bumping up the required majority from 51 to at least 60. 

That means a death sentence for any bill not enjoying hefty opposition support.

Republicans are clear they will use the filibuster to kill the voting rights bills, which they argue would undermine, not strengthen democracy by shifting power from state authorities to the federal government.