ATLANTA -- U.S. President Donald Trump's first political rally since losing his reelection bid is ostensibly to urge support for the Republican incumbents in Georgia's two runoffs that will decide which party controls the Senate at the start of Joe Biden's administration.

But the question remains whether Trump will really try to help his party or use the Saturday night event in Valdosta to amplify his conspiratorial and debunked theories of electoral fraud.

Republicans are worried that if Trump does the latter, their voters will think the system is rigged and decide to sit out the two Jan. 5 races. They want Trump to tell people directly and forcefully to vote.

The president's aides publicly scoff at the idea he might do anything other than encourage Republicans to back Sens. David Perdue and Kelly Loeffler as they try to withstand Democrats Jon Ossoff and Raphael Warnock, respectively.

"I believe it's the start of these two senators crossing the finish line," White House press secretary Kelly McEnany said on the eve of Trump's visit. McEnany credited Trump with being his party's biggest turnout driver, noting that Republicans narrowed House Democrats' majority while several vulnerable Republican senators survived challenges by comfortable margins.

Trump's base "is behind him all the way," she told Fox Business Network. "He is the head of this movement, make no mistake, and that will not be changing."

But after two pro-Trump lawyers this past week questioned whether voting again is even worth it -- in echoes of the president's baseless accusations of widespread voter fraud -- even Vice-President Mike Pence betrayed concerns that the Republican coalition could crack under the force of Trump's grievances.

"I know we've all got our doubts about the last election, and I hear some of you saying, `Just don't vote,"' Pence said Friday while campaigning with Perdue in Savannah. "If you don't vote, they win."

Republicans need one more seat for a Senate majority. Democrats need a Georgia sweep to force a 50-50 Senate and position Vice-President-elect Kamala Harris as the tiebreaking majority vote.

Few Republicans in Washington or Georgia believe wide swaths of the electorate in this newfound battleground would opt out of voting because of Trump's false claims or his denigration of the Georgia governor and secretary of state for certifying Biden's victory in the state.

The risk for the GOP is that it wouldn't take much of a drop-off to matter if the runoffs are as close as the presidential contest: Biden won Georgia by about 12,500 votes out of 5 million cast. There's enough noise to explain why Pence felt the need to confront the matter head on after two Trump loyalists floated the idea of the president's supporters bailing on Perdue and Loeffler.

"I would encourage all Georgians to make it known that you will not vote at all until your vote is secure -- and I mean that regardless of party," lawyer Sidney Powell said this past week at a suburban Atlanta "Stop the Steal" rally.

Atlanta celebrity lawyer Lin Wood, who's filed thus-far unsuccessful court challenges to Biden's victory, insisted to Trump's supporters that the state's elections are "rigged."

Trump's team has recently tried to dissociate itself from the pair but only after they were given a prominent platform in the flailing effort to overturn the presidential election results. Moreover, Trump personal lawyer Rudy Giuliani returned Thursday to the Georgia Capitol for a marathon hearing that featured yet another airing of disproved claims.

Trump has been the source of party angst with his recent declarations that Georgia Gov. Brian Kemp is "hapless" and Secretary of State Brad Raffensperger is an "enemy of the people" because they didn't block Biden's Georgia victory. State law gives them no avenue to do so.

It's resonated with voters such as Barry Mann, a 61-year-old business owner who came to hear Pence in Savannah. Mann hasn't decided whether he'll vote for his senators a second time.

"I think there's some issues with our election and more investigation needs to be done," Mann said, adding that he doesn't think Perdue and Loeffler have done enough to support Trump's efforts to overturn the results. "I want see what happens between now and January," Mann said.

A third vote count, this one requested by the president's reelection campaign, was nearing completion. Raffensperger could certify the election again as soon as Saturday; the result is not expected to change.

Tim Phillips, president of the conservative Americans for Prosperity, played down the idea that there are enough voters like Mann to cost Perdue and Loeffler. Phillips' group has about 200 field workers canvassing across Georgia.

After his own door-knocking shift Friday, Phillips described the GOP's pool of potential voters, especially in rural and small-town areas, as largely "voters who aren't so much Republicans or even conservatives, but they love Trump." That loyalty, he said, allows them to "hear two different messages" from Trump.

"He may say some things about the governor or other people, but the dominant message is that he's down here for Perdue and Loeffler," Phillips said. That should be "enormously beneficial."

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Associated Press writer Russ Bynum in Savannah, Georgia, contributed to this report.