Trump's criticism of GOP Senate candidates has Republicans worried ahead of rally

President Donald Trump heads to Georgia on Saturday to campaign for two Republican senators one month ahead of a critical runoff that will determine which party controls the Senate. But Trump's visit comes as he has spent the last several weeks consumed by his own election loss while attacking party officials in the state, casting doubt on its voting process and questioning one of the lawmakers he's urging voters to elect.

According to two sources, during a recent phone call Trump blasted Georgia Republican Gov. Brian Kemp as a "moron" and "nut job" and asked why Sen. Kelly Loeffler did not secure a majority of votes on Election Day, placing her in a runoff against the Democrat Rev. Raphael Warnock. Last December, Trump had lobbied Kemp to fill the seat vacated by Johnny Isakson with Doug Collins, not Loeffler, but Kemp appointed Loeffler anyway -- a factor Trump has harped on in recent days.

Trump's private and public broadsides have raised concerns among Republicans that his interference could do more harm than good in the pivotal races.

If Democrats can win both races, it will dramatically change the trajectory of the first two years of Joe Biden's presidency. It would make the Senate a 50-50 tie between the two caucuses, allowing Vice President-elect Kamala Harris the deciding vote -- giving him much greater leeway in naming his Cabinet and confirming judges. But if the Republicans pick off just one of the seats, Senate Majority Leader Mitch McConnell will retain control of the chamber, forcing Democrats into a much more compromising position.

But Trump's impending campaign rally in Georgia has some Republicans on edge, concerned Trump could depress turnout among his base if he continues to rail against Georgia's election system and launches more attacks against Kemp.

"It's not helpful if he goes down there and attacks the governor for an hour and a half. But really, what needs to happen is he needs to say a couple things -- the right things -- that will be loaded into a teleprompter and that we can cut up and use for TV," a Trump adviser said. "If he says the few things that we need him to say, it'll be helpful."

Trump praised QAnon during meeting about keeping the Senate

Despite his popularity with Republicans, Trump was reluctant to campaign in Georgia and grudgingly agreed to visit one month before the critical race after being lobbied by several allies, according to multiple sources.

Perdue and Loeffler both called Trump before Thanksgiving, urging him to come campaign in their state ahead of the runoff, a Republican familiar with the conversation said.

Others, such as Republican National Committee Chairwoman Ronna McDaniel, have also encouraged Trump to campaign in Georgia, plying him with the prospect that he can take credit for a Loeffler and Perdue victory in January if he campaigns in the Peach State.

Trump will hold a rally at an airport hangar in Valdosta, Georgia on Saturday following a visit by Vice President Mike Pence to the state Friday. Kemp, who Trump called "hapless" this week, had been scheduled to meet Pence on the tarmac but canceled at the last minute over a "family emergency." It's not clear if he will meet Trump on the tarmac Saturday.

Several sources who have spoken with Trump in recent days described a President more obsessed with his own election loss than preserving the power of Republicans in the Senate, despite how many members of his party have privately expressed a desire to put the 2020 election behind them and focus on the Georgia runoff.

Trump taped a 46-minute video this week that was mainly filled with recycled grievances and lies about the election, despite his own attorney general stating this week that the Justice Department had uncovered no evidence of voter fraud that would change the election outcome. Trump questioned how Republicans could have fared so well in the 2020 race while he lost.

"It is statistically impossible that the person, me, that led the charge lost," Trump falsely claimed in the video.

Trump's rally is being funded by the RNC instead of his campaign, which usually foots the bill, but not because of a lack of cash. In the last month, Trump's campaign has inundated supporters with fundraising appeals over his baseless claims the election was rigged. Refusing to concede the White House race has proved to be a lucrative endeavor for the President, given his political operation has raised more than $207 million since Election Day.

Asked about Trump's reluctance to travel to the state, Trump campaign communications director Tim Murtaugh told CNN: "Control of the US Senate is on the line in Georgia's two runoff elections and the President knows it's imperative that Sen. Perdue and Sen. Loeffler are successful. The President is going to Georgia to rally Republicans and remind them what's at stake."

CNN reported this week that Georgia Republicans are increasingly worried about Trump's rally as some brace for a tirade to overturn his loss that could hurt the party's effort to keep control of the chamber. A group of prominent former Georgia Republican officials, including former Gov. Nathan Deal and former Sens. Isakson and Saxby Chambliss, released a statement on Wednesday urging the party to unify and to shift attention to the challenge of protecting their Senate majority.

When asked if he thought the President would change his tune on Saturday, Chambliss told CNN that he does not predict what Trump will do. "And that's part of the concern that I have," he said.

"I want him coming down here talking about Kelly and David, and how important they are to the future of the country, and how their election is so critical to his legacy," said the former senator. "If he wants his legacy to remain, then he needs to ensure that we win both these seats -- and he needs to say that in no uncertain terms."

Trump's team and the RNC have been coordinating with the Perdue and Loeffler campaigns to get out the vote in Georgia. Donald Trump Jr. has made it clear that his father's supporters need to back the GOP ticket. Trump Jr. is starring in a series of ads that will air on conservative media outlets designed to get out the Trump vote.

CNN's Alex Rogers and Ryan Nobles contributed to this report.