Donald Trump's public spat with his party will shift even more focus to already expensive Senate races as the Republicans try to hang on to control of Capitol Hill.
House Speaker Paul Ryan told fellow lawmakers this week he will focus the election's final weeks on keeping GOP majorities in Congress rather than defending his party's presidential nominee. While the Republican National Committee and Trump's campaign insist their relationship has not changed, the party and its major donors could follow Ryan's lead in refocusing down ballot.
Prior spending indicates cash could trickle down to several crucial races in the Senate. Many of those feature Republican incumbents trying to hold off Democratic challenges as they walk a tightrope between distancing themselves from an increasingly toxic Trump and holding on to the businessman's most fervent supporters.
Candidate committees and outside groups like super PACs on both sides have spent at least $320 million on just five Senate races — in Pennsylvania, New Hampshire, Ohio, Florida and Nevada — according to the Center for Responsive Politics. All of those races accept Nevada feature an incumbent Republican senator, and pro-GOP forces have heavily outspent pro-Democrat groups in the contests with Republican senators.
That huge spending should only continue if the GOP shifts its focus from Trump. Campaign and outside groups backing him have raised and used considerably less money than groups supporting most recent presidential nominees.
Democrats need to gain four seats to control the Senate if Hillary Clinton wins, or five if Trump wins. The party faces a much tougher task in taking control of the House, even with the GOP spat.
Spending so far indicates the Republicans will focus on tight Senate races in New Hampshire and Pennsylvania, which "look like hot spots right now," said Steven Billet, director of the masters program in legislative affairs at George Washington University's Graduate School of Political Management. The Pennsylvania race pitting GOP Sen. Pat Toomey against Democrat Katie McGinty is already more expensive than the costliest race in the 2012 cycle. In that year, campaigns and outside groups poured about $85 million into the race between Democratic Sen. Elizabeth Warren and then-Republican incumbent Scott Brown.
Billet noted that some cash could also shift to key races in Missouri, North Carolina and Nevada.
He added that the Republican National Committee had more than $40 million on hand at the end of August and it would have to decide whether to shift those resources down ballot.
"The question is what the party will do with that money. Are they going to try to save Donald Trump or save the Senate?" he asked.
The Trump campaign has decided to pull out of Virginia, according to NBC News, focusing instead on Pennsylvania, Florida, North Carolina and Ohio, which are crucial to any chance he has of winning the presidency.
The Republican Party and donors could also focus their down-ballot efforts on those states, said David Kochel, a Republican strategist who previously worked with Mitt Romney and Jeb Bush.
"I think the thing to do is what Paul Ryan suggested, which is just we ignore the Trump campaign as they're in full meltdown," Kochel told CNBC's "Squawk on the Street" on Thursday.
Congressional campaign committee spending only goes through the end of June, as the organizations file reports to the Federal Election Commission on a quarterly basis. Outside groups file reports monthly.
The next quarterly reports are due Saturday.