WASHINGTON — (CNN) The super PAC backed by Senate Majority Leader Mitch McConnell is sprinting full bore to finance a late advertising barrage and save the Senate for Republicans, pulling in $43 million this month.

The Senate Leadership Fund will report Thursday a $25 million fundraising haul over this past week, according to SLF spokesman Ian Prior, suggesting that the group received several multi-million dollar checks as the GOP majority grew imperiled — or perhaps one gargantuan one.

The group also raised $7 million from its donors in the first 20 days of October.

The super PAC has flipped that money almost immediately into a new advertising push in a half-dozen states financed entirely by the late checks. Those contributions will not be reported until December, though many expect Sheldon Adelson, the top Republican giver who together with his wife donated $20 million to the PAC this summer, to have given more.

Prior said that One Nation — a nonprofit also part of the American Crossroads suite of big-money GOP groups — has also sent over an additional $11 million to to the super PAC, a maneuver that gives the network more flexibility in advertising.

One Nation is not required to disclose its donors as long as it does not spend more than half of its money directly on elections, and Prior described it as “a part of One Nation’s political activity that’s allowed under the law.”

In total, the $32 million in new money for the PAC is likely to even the playing field as Democrats largely outspend them in most states. The Crossroads network has borne much of the advertising brunt this fall given meager advertising from presidential candidate Donald Trump and a retrenchment from the airwaves this October by the groups funded by Charles and David Koch.

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