Retired Marine Corps General James Mattis is not going to run a third-party campaign if Donald Trump becomes the Republican nominee.

Weekly Standard editor Bill Kristol was trying to get Mattis to run as part of his scheme to run an independent in the general election against Trump and Hillary Clinton. Such a plot would presumably siphon votes away from Trump and help Clinton. Stopping Trump would allow Kristol to keep his finger in the pie in the 2020 Republican primary.

“The thoughtfulness and patriotism — and for that matter, the modesty — Jim showed as he reflected on this decision make me more convinced than ever that he would have made a truly admirable president, and also a good candidate. But it’s not to be. So we won’t have a President Mattis,” Kristol told The New York Times Friday.

The Republican National Committee told Breitbart News that Kristol’s proposed third party, “The Latter-Day Republicans,” does not have the committee’s support and is only “helping to elect Hillary Clinton.”

Kristol has considered Tom Coburn and Rick Perry for a third-party run and also has speculated that Mitt Romney and Marco Rubio could be part of such a ticket.