The fiercest Republican campaign isn’t taking place between the presidential hopefuls in Iowa or New Hampshire this month, but rather in the backstage fight over who would be Donald Trump’s running mate. Or more to the point: who will not be Trump’s pick.

As Nikki Haley emerges as the former president’s most formidable opponent in the coming states, and toughens her rhetoric, her Trumpworld foes are intensifying their own efforts to block her from the consolation prize of the vice presidency.

Haley’s critics have even privately warned Trump that, were he to make Haley first in line to the presidency, he’d effectively be setting himself up for an intra-party coup, as GOP senators would use any legal or political pretext to remove him from office and elevate the more old guard-aligned Haley.

“Nikki Haley as VP would be an establishment neocon fantasy and a MAGA nightmare,” Rep. Matt Gaetz (R-Fla.) told me. “On Day One she would convert the Naval Observatory into an anti-Trump, resistance headquarters, undermining him at every step.”