Nikki Haley is projected to win Vermont’s Republican primary, handing a surprise Super Tuesday defeat to former US President Donald Trump.
It would be the ex-UN envoy’s biggest primary season win so far, following her first-place finish in Washington DC’s nominating vote at the weekend.
But it’s a mere speed bump for Republican front-runner Mr Trump on a night where he otherwise dominated.
He is on course to clinch his party’s White House nomination this month.
Vermont did not have many opinion polls before Super Tuesday, although the surveys that were carried out had indicated a comfortable lead for Mr Trump.
But the Green Mountain state has a stubborn independent streak, and its Republican Governor Phil Scott is an outspoken Trump critic who campaigned for Ms Haley at a rally with her in Burlington on Sunday.
It is not clear whether victory in Vermont could give a fresh lease of life to Ms Haley’s longshot campaign.
Speculation has been mounting in recent days that she may soon drop out as Mr Trump’s last remaining challenger. The former president looked set to win the 14 other states and one US territory which voted on Tuesday.
Ms Haley, the former governor of South Carolina, told Fox News on Tuesday morning she had not yet made a decision about her future.
The Haley campaign said there was nothing on her calendar for Wednesday.
