On the day of the crucial Senate runoffs in Georgia, the GOP is at war with itself

• On the day of the crucial Senate runoff elections in Georgia that will determine control of the US Senate, the GOP is divided.
• President Donald Trump has attacked state and congressional Republican leaders who refused to back his bid to overturn the presidential election.
• Splits also came over COVID-19 stimulus checks. Trump and both Georgia candidates back $2,000 payments, which were blocked by Senate Majority Leader Mitch McConnell.
• The president in a tweet last week even attacked the validity of Tuesday's elections. Some fear this could reduce turnout when Republicans need it most.
• Even so, Democrats need to win both Senate races to wrest control from the GOP, which remains a tall order.

As voters in Georgia head to the polls to decide whether Republicans or Democrats will control the US Senate, the GOP is torn by infighting.

Still pursuing his groundless claims that the presidential election was stolen from him, President Donald Trump has turned on the party's leadership in the state and in Congress.

While he and many loyalists assert that the election was stolen, a large contingent of congressional Republicans accept that Joe Biden won the White House in November and are preparing to certify the result.

This has placed the Republican Party's runoff candidates - Sens. David Perdue and Kelly Loeffler - in a bind.

Instead of presenting a unified front, they have been forced to choose between Trump, who retains enormous popularity among the grassroots Republicans, and the congressional leaders who will be the top elected GOP figures when Trump's term ends January 20.

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So far, both Senate candidates have opted to back the president, securing them his prized endorsement at a rally held in the state on the eve of the election.

Both Perdue and Loeffler backed Trump's demands for $2,000 direct payments as part of the recent package of economic coronavirus relief, putting them at odds with Senate Majority Leader Mitch McConnell, who effectively ended Trump's demand for more cash over the holidays.

The split has unquestionably hobbled parts of the GOP reelection efforts.

Trump in pursuing his election-fraud quest has attacked the integrity of the runoffs themselves, tweeting on Friday that the races were "illegal and invalid."

He has since changed tack and encouraged his base to vote, but his repeated assertions of fraud may have succeeded in keeping some Republican voters home.

The president's obsession has also damaged the GOP's core message ahead of the runoffs, weakening the urgency with which they could claim they need to retain the Senate to hold back Biden.

If Republicans lose both seats, the Senate goes with it. They and the Democrats (including two independents) would hold 50 seats each, with a tiebreaker vote for Vice President Kamala Harris.

But sketching out this scenario requires acknowledging that Trump lost. Under a genuine belief that Trump and Mike Pence will remain in office after January 20, GOP Senate control would not be at risk.

In November, the Republican National Committee's chairwoman, Ronna McDaniel, deleted a campaign tweet asserting the stakes of the Georgia race because it mentioned a future Biden-Harris administration.

Polling averages gathered by FiveThirtyEight actually show both Perdue and Loeffler falling behind their Democratic challengers, Jon Ossoff and Raphael Warnock, in the weeks since Trump intensified his attacks against GOP leadership, though the latest results are well within the margin of error.

But despite the chaos in their party, Republicans' job on Tuesday is in one key respect easier.

They must win only one of the two races to maintain control of the Senate, while Democrats need both victories for the chamber to change hands.