Sen. Ted Cruz (R-TX) is pulling in the big guns, from PACs to President Donald Trump, to help him shore up his re-election bid in a race that’s looking increasingly uncertain thanks to the robust challenge by Democratic Rep. Beto O’Rourke.

According to a Sunday Politico report, the Republican powers-that-be were getting concerned about the former GOP stronghold two months ago, sending Texas Lt. Gov. Dan Patrick to lobby the White House on Cruz’s behalf. Soon after, Trump announced an October rally for Cruz.

This is part of a larger push within the GOP to divert resources to Cruz’s campaign, considered a safe Republican hold before O’Rourke’s challenge and notable fundraising success, per Politico.

“We’re not bluffing, this is real, and it is a serious threat,” Sen. John Cornyn (R-TX) told Politico. “If Ted does his job and we do ours, I think we’ll be fine. But if we have donors sitting on the sidelines thinking that, ‘Well, this isn’t all that serious,’ or ‘I don’t need to be concerned,’ then that’s a problem.”

Cruz is reportedly personally reaching out to big donors and PACs are spending heavily in the race.

The closely-watched election came to the fore again this weekend, when OMB Director Mick Mulvaney made (since leaked) comments in a closed-door event with donors about the severity of the situation and the very real possibility that Cruz could lose.