After a lengthy vacation in Europe, followed by a blowout PayPal reunion party at his mansion in Los Angeles last weekend, Peter Thiel has returned to reality to deal with more immediate concerns: How to elect his two Republican protégés to the U.S. Senate.

Thiel has had an incredible run in the 2022 midterms cycle, placing two $15 million bets in Ohio and Arizona to transform J.D. Vance and Blake Masters, respectively, from middle-of-the-pack primary candidates into G.O.P. Senate nominees. But behind the scenes, sources familiar with the talks tell me, Thiel’s team has spent the summer engaged in months-long, high-stakes, sometimes tense negotiations with allies of Mitch McConnell about who is going to finance the advertising barrage required to carry Vance and Masters over the finish line. As I previously reported, McConnell’s team reached out to Thiel around late April for another $20 million, to be deposited in McConnell’s super PAC, to boost the two candidates through November. That didn’t happen. Thiel, despite being worth some $7 billion these days, can be surprisingly frugal—and, apparently, highly sensitive to feeling extorted. After all, isn’t it McConnell’s job to elect G.O.P. nominees?

And so, for the last few months, the standoff between Thiel and McConnell has become a game of chicken. But time is running out: It is almost Labor Day, and both of the Thiel-funded PACs supporting Masters and Vance are effectively broke, with neither having ads reserved in either Arizona or Ohio for the final weeks of the race. Some G.O.P. insiders and pro-Thiel forces, facing the prospect of fumbling the Senate, are wringing their hands over who exactly will be spending the money needed to beat Mark Kelly in Arizona and a surprisingly competitive Tim Ryan in Ohio.