By Jonathan Swan - 09-07-16 10:39 AM EDT
Outside groups supporting Senate Republicans had their biggest fundraising month ever, bringing in $42 million in August.
The stunning size of the cash haul by two groups with close ties to Senate Majority Leader Mitch McConnell (R-Ky.) is a perfect measure of the anxiety levels Republican donors are feeling about Democrats winning back the Senate this year.
"This is without a doubt the best single month of fundraising we have ever had for our groups," said Ian Prior, communications director for both the Senate Leadership Fund super-PAC, which raised $28.2 million in August, and an affiliated non-profit, One Nation, which raised $14.2 million.
"This is a testament to just how important it will be to keep GOP Senate majority in 2016," Prior added, in a statement to The Hill on Wednesday.
The two groups have now raised $100 million for the cycle to date, according to Prior.
The fundraising figures were first reported by Politico and have been confirmed to The Hill.
Steven Law, who runs both groups, is also in charge of American Crossroads and Crossroads GPS - outfits founded by Republican strategist Karl Rove that played a major role in the 2010 and 2012 elections.
Law told Politico that Trump's terrible slide in the polls after the Republican National Convention in Cleveland - a period in which he engaged in a damaging fight with the family of a fallen war hero - jolted the donor class into action.
"A lot of it was driven by Trump's post-convention performance. It was a major galvanizing factor where donors decided they wanted to invest in something," Law told Politico.
"They were very concerned about the state of the presidential race and the idea of fighting to protect the Senate majority gave them a sense of mission and urgency and it was not a hard sell when we started contacting them in the month of August."
Prior told The Hill that Senate Leadership Fund has already booked about $60 million in TV ads in seven battleground states.
That money will help Reps. Joe Heck and Todd Young in their Senate races in Nevada and Indiana as well as Sen. Kelly Ayotte in New Hampshire, Sen. Pat Toomey in Pennsylvania, Sen. Roy Blunt in Missouri, Sen. Richard Burr in North Carolina and Sen. Rob Portman in Ohio.
The McConnell-linked groups appear to view two vulnerable incumbent Republican senators as beyond saving: Mark Kirk in Illinois and Ron Johnson in Wisconsin.
This report was updated at 11:49 a.m.