Florida Governor Ron DeSantis ended his fading presidential campaign on Sunday and endorsed Donald Trump just two days before the pivotal New Hampshire primary, leaving former UN Ambassador Nikki Haley as Trump’s last long-shot challenger for the Republican nomination.

DeSantis’ decision, less than a week after his deflating loss to Trump in Iowa despite an enormous investment there, caps a stunning fall from grace after DeSantis had been widely seen as Republicans’ most promising alternative to Trump ahead of the general election in November.

His departure sets up the one-on-one battle that Haley has coveted against Trump, the former president who has maintained an iron grip on the Republican electorate despite facing four criminal prosecutions. Trump has pleaded not guilty in all the cases.

But DeSantis’ supporters appear more likely to switch allegiance to Trump than to the more moderate Haley. In New Hampshire, about two-thirds of DeSantis backers cite Trump as their second choice, said Andrew Smith, director of the University of New Hampshire Survey Center.