San Francisco Frontiers - Biden, Trump clash on eve of midterms set to upend Washington

More than 40 million ballots have been cast through early voting options, meaning the fate of the world's biggest economy was already in play, with hours to go before polls open nationwide Tuesday.

Adding to tensions -- and a reminder of the international stakes -- Kremlin-connected oligarch Yevgeny Prigozhin boasted that Russia was trying to tilt the outcome.

"We interfered, we are interfering and we will interfere... carefully, precisely, surgically and the way we do it, the way we can," said Prigozhin, a pivotal figure in the Ukraine invasion where his Wagner military contractor group is on the front lines.

Biden, who has framed his closing argument as a warning that American democracy is on the line, was set to close out days of frantic campaigning for Democratic candidates at a rally Monday evening near Baltimore.

Trump, who is using the midterms to repeatedly tease a possible 2024 White House run, was holding a rally in Ohio.

With polls showing Republicans in line to seize the House of Representatives, the increasingly far-right party eyed snarling the rest of Biden's first term in aggressive investigations and opposition to spending plans.

Kevin McCarthy, who would likely become speaker of the House -- placing him second in line to the president -- also refused to rule out impeachment proceedings.

"We will never use impeachment for political purposes," McCarthy told CNN. "That doesn't mean if something rises to the occasion, it would not be used at any other time."

One key question remained whether the US Senate would also flip, leaving Biden as little more than a lame duck.

With Congress out of Democrats' hands, Biden would see his legislative agenda collapse.

That would raise questions over everything from climate crisis policies, which the president will be laying out at the Cop27 conference in Egypt this week, to Ukraine, where Republicans are reluctant to maintain the current rate of US financial and military support.

While insisting he supports Ukraine's struggle, McCarthy told CNN that there could be no "blank check" -- a nod to the isolationist, far-right Trump wing of his party and a signal likely sending shivers through Kyiv.

Just how bad Tuesday goes will also likely determine whether Biden, who turns 80 this month and is the oldest president ever, will seek a second term or step aside, plunging his party into fresh uncertainty.

- 'Wake-up call' -

Up for grabs are all 435 House seats, a third of the 100 Senate seats, and a slew of state-level posts.

Popular former president Barack Obama and other Democratic stars have been racing from campaign to campaign in hopes of seeing off the predicted Republican "red wave."

But the political landscape has been tilting away from Democrats since the summer, as Republican messaging about high inflation, crime and illegal immigration overwhelmed the incumbents.

"This is going to be a wake-up call to President Biden," was the bullish weekend prediction of Glenn Youngkin, Virginia's Republican governor and a rising star being touted as a possible party alternative to Trump in 2024.

The Senate is more of a toss-up but Democratic hopes of keeping the upper chamber, which they currently only barely control thanks to the tiebreaking vote from Vice President Kamala Harris, hang in the balance.

Dave Wasserman of the nonpartisan Cook Political Report said Republican candidates have "a little more upside" with late-deciders.

Wasserman told MSNBC there could be a Republican gain of 15-25 House seats, while "Republicans might gain the one seat they need to win control of the Senate."

Races in Pennsylvania, Nevada, Arizona, Georgia, Wisconsin, New Hampshire and Ohio have narrowed to projected photo finishes, and any one of them could swing the balance of power.

Democrats have focused their closing arguments on voting rights, protecting abortion access and welfare -- and on the threat posed by growing support among Trump Republicans for political conspiracy theories.

The Republicans counter that a vote for Democrats means more soaring inflation and rising violent crime, seeking to make the midterms a referendum on the president.

With his own approval rating marooned around 42 percent, Biden has largely avoided campaigning in the most contentious states.

L.Ramos--SFF