Republican presidential candidate former UN Ambassador Nikki Haley speaks at a campaign event on Monday, Feb. 19, 2024, in Greer, S.C. (AP Photo / David Yeazell)

Haley didn’t endorse the former president in a speech in Charleston, South Carolina. Instead, she challenged him to win the support of the moderate Republicans and independent voters who supported her.

A voter walks to a Michigan primary election location in Dearborn, Mich., Tuesday, Feb. 27, 2024. Michigan is the last major primary state before Super Tuesday and a critical swing state in November's general election. (AP Photo / Paul Sancya)

Joe Biden and Donald Trump easily won their party’s primaries in Michigan, but Tuesday’s results showed that both candidates have cause for concern in their bid to win the swing state in November.

Joe Biden and Donald Trump. (AFP/Getty Images via CNN Newsource)

Biden’s campaign entered February with nearly $56 million cash reserves in his main campaign committee compared to a little more than $30 million in the coffers of Trump’s equivalent account.

Republican presidential candidate former UN Ambassador Nikki Haley speaks at a campaign event on Monday, Feb. 19, 2024, in Greer, S.C. (AP Photo / David Yeazell)

Ahead of a major speech on Tuesday, Haley told The Associated Press that she’s staying in the race no matter what at least until after another 20 states vote through Super Tuesday on March 5. That’s even as Donald Trump’s MAGA movement is furious that she’s refusing to drop out. After all, she’s the last major candidate standing in his path to the nomination.

Republican presidential hopeful Nikki Haley speaks with supporters Jan. 15, 2024, in Des Moines, Iowa. (AP Photo / Meg Kinnard, File)

The indignity of a distant second-place finish behind “none of these candidates” was a fresh blow for Haley, facilitated by the staunch Trump allies who lead Nevada's GOP. 

Republican presidential candidate former President Donald Trump addresses members of the press during a campaign stop in Londonderry, N.H., Tuesday, Jan. 23, 2024. (Matt Rourke / AP Photo)

The result was a setback for former U.N. Ambassador Nikki Haley, who finished second despite investing significant time and financial resources in a state famous for its independent streak. She’s the last major challenger after Florida Gov. Ron DeSantis ended his presidential bid over the weekend.

Nick Zaharias of Derry, N.H., a public witness, loads a test ballot into a vote counting machine while testing machines before the New Hampshire primary, at the Derry Municipal Center, Tuesday, Jan. 16, 2024. (AP Photo / Charles Krupa)

With Ron DeSantis ending his 2024 campaign and endorsing Donald Trump on Sunday, the Tuesday primary becomes the first one-on-one matchup between Trump and Nikki Haley.

Republican presidential candidate former President Donald Trump takes the stage at a caucus night party in Des Moines, Iowa, Monday, Jan. 15, 2024. (AP Photo / Andrew Harnik)

About 7 in 10 Iowans who caucused for Donald Trump on Monday night said they have known all along that they would support a man who has remade the Republican Party through his “Make America Great Again” political movement. 

GOP presidential hopeful Nikki Haley speaks during a campaign event on Monday, Nov. 27, 2023, in Bluffton, S.C. (AP Photo / Meg Kinnard)

Despite seizing polling momentum in recent months, the former United Nations ambassador’s campaign has been lacking significant manpower on the ground in primary states to ensure her supporters turn out to vote. 

Former Vice President Mike Pence, left, speaks to reporters before the MockCon event at University Chapel at Washington and Lee University on Tuesday, March 21, 2023, in Lexington, Va. (Scott P. Yates / The Roanoke Times via AP)

From Florida Gov. Ron DeSantis to former Vice President Mike Pence and South Carolina Sen. Tim Scott, there appears to be little rush to join the field of official presidential candidates. The reluctance reflects the unsettled nature of U.S. politics.

Former U.N. Ambassador Nikki Haley speaks at an annual leadership meeting of the Republican Jewish Coalition, Nov. 19, 2022, in Las Vegas. (AP Photo / John Locher, File)

The announcement, delivered in a tweeted video, marks an about-face for the ex-Trump Cabinet official, who said two years ago that she wouldn’t challenge her former boss for the White House in 2024.