The Senate minority leader, Mitch McConnell, appears to be planning a Labor Day rescue mission for Republican efforts to recapture the Senate, even as President Trump escalates tensions by calling for his replacement.

The Senate Leadership Fund, a political action committee closely aligned with Mr. McConnell, is set to spread $178 million among the Republican Party’s various senatorial candidates.

The spending will help close the gap between Republicans and Democrats in the battle for the Senate this year, and couldn’t come a moment too soon. As the Sun has reported, Republican Senate candidates are beginning to beg for money in emails to their supporters.

The Democratic Party’s funding superiority so far this cycle has allowed them to dominate the airwaves, defining the races in competitive states including Pennsylvania, Georgia, and Ohio.

Republicans have been forced to pivot to defense, narrowing their focus on seats that should be a breeze for the GOP to win, such as Ohio, at the cost of spending in states they had earlier hoped to flip, like Colorado.

Even after the infusion of Mr. McConnell’s money, Republicans will be trailing Democrats in spending this year.

Democratic Senate candidates have taken an early lead in most competitive races, including Arizona and Nevada, where they are protecting their own seats, as well as Wisconsin and Pennsylvania, where they are aiming to flip Republican seats. Even the Senate race in Florida is shaping up to be competitive.

The Republicans are hoping that this latest injection of cash will help them curb the growing Democratic momentum. Democrats have been outperforming expectations in both elections and fundraising since the Dobbs v. Jackson ruling that overturned Roe v. Wade.

The new wave of red money also has certain Trump-backed candidates, who resisted Mr. McConnell’s influence in the past, kowtowing to the minority leader. 

The venture capitalist who is the Republican nominee for Senate in Arizona, Blake Masters, earlier had supported ousting Mr. McConnell from his leadership position. He has since changed his tune.

Mr. Masters recently told the Associated Press that he thinks Mr. McConnell will continue in his Senate leadership position following 2022. Perhaps coincidentally, the Senate Leadership Fund is lined up to drop some $14.4 million into the Arizona Senate race.

“I think I’m a much better candidate than Mitch McConnell gives me credit for,” Mr. Masters told the Associated Press. “Arizona’s gonna be competitive. It’s gonna be a close race, and I hope he does come in.”

Meanwhile, Mr. Trump and his Save America political action committee are keeping its purse closed, even as candidates that Mr. Trump’s influence propelled to the nomination — like Mr. Masters — struggle to compete with Democrats.

The Senate Leadership Fund spending surge comes at the perfect time to counter growing whispers that the minority leader might be willing to let Mr. Trump’s candidates sink, following Mr. McConnell’s gripes about “candidate quality” and his feud with Mr. Trump.

Thursday, Mr. Trump called for the immediate replacement of Mr. McConnell as the Republican leader in the Senate.

“Mitch McConnell is not an Opposition Leader, he is a pawn for the Democrats to get whatever they want,” Mr. Trump said in a statement on Truth Social. “A new Republican Leader in the Senate should be picked immediately.”

Although Mr. Trump will rail against the Senate minority leader online, he doesn’t appear to be willing to compete with him in terms of funding efforts by Republicans to take the Senate.

Mr. Trump, in spite of his online posturing, has thus far spent more of his Save America PAC funds on legal fees and portraits of his wife than on campaigns for Republican candidates.