Donald Trump won South Carolina's Republican primary on Saturday, AP projects, in an embarrassing double-digit blow to former UN Ambassador Nikki Haley in her home state.

Why it matters: Haley has vowed to stay in the primary beyond South Carolina, but her path forward looks increasingly far-fetched.

• Trump, who clinched all 29 of the state's at-large delegates, has cruised to victory in every GOP primary contest, and he already holds a strong delegate advantage. He spoke at CPAC outside Washington earlier Saturday and didn't mention Haley directly in his victory speech.
• Haley, who served as governor of South Carolina for six years, had trailed Trump by double digits in her home state ahead of Saturday.
• Trump also amassed an endorsement advantage, winning the backing of most of the state's most high-profile lawmakers.

What they're saying: "I have never seen the Republican Party so unified as it is right now," Trump said during remarks after his projected win.

• "This is a fantastic evening, it's an early evening."
• "You can go down and celebrate for about 15 minutes and then we have to get back to work."

Trump was joined on stage during his victory speech by South Carolina Gov. Henry McMaster, Sens. Sen. Tim Scott and Lindsey Graham (R-S.C.) and Reps. Marjorie Taylor Greene (R-Ga.) and Nancy Mace (R-S.C.), among others.

Haley congratulated the former president during remarks after her projected loss and reaffirmed her vow to stay in the race.

• "I am a woman of my word," she said, continuing: "I'm not giving up this fight when the majority of Americans disapprove of both Donald Trump and Joe Biden."
• She added that American voters have a "right to a real choice."
• "I'm grateful that today is not the end of our story," she said, adding that she is heading to Michigan Sunday before the state's Tuesday primary.

State of play: There were 50 delegates up for grabs in South Carolina, and the statewide winner gets 29.

• South Carolina Republicans have an open primary, meaning any registered voter could participate unless they are part of the approximately 4% of registered voters who already cast a ballot in the Feb. 3 Democratic primary.

Between the lines: South Carolina has a strong track record of picking the party's eventual nominee.

• Since 1980, only one candidate, Mitt Romney, secured the party's nomination without winning the Palmetto State.
• No nominee from either party has lost their home state during a primary during the modern primary era, CNN notes.

Zoom in: Following Trump's decisive victories during the Iowa caucuses and New Hampshire primaries, prominent Republicans amped up their calls for Haley to suspend her campaign and unify around the former president.

• Haley addressed the skeptics during a speech earlier this week, saying she is "not afraid to say the hard truths out loud."
• "I have no fear of Trump's retribution. I'm not looking for anything from him," she said during remarks in Greenville, South Carolina.

The big picture: Haley and Trump have sharpened their attacks on each another in the month since the New Hampshire primary, where the former president won by over 10 points.

• Haley during the same speech earlier this week said that Trump "has gotten more unstable and unhinged" and "meaner and more offensive by the day."
• Trump advisers in a memo on Tuesday said that Haley does not have a path to securing the nomination and said she was "like any wailing loser hellbent on an alternative reality."

What's next: Haley has pinned much of her long-shot path forward on open primaries in at least 13 states to give her any gain over Trump.

Editor's note: This story has been updated with additional details and developments.