Former President Trump is dominating the endorsement race in former UN Ambassador Nikki Haley's home state of South Carolina.

Why it matters: The Trump campaign has built a powerful firewall using many politicians who'd otherwise be expected to back Haley — and he's already started to flex the advantage.

• Reps. Nancy Mace and Jeff Duncan this week became the latest South Carolina Republicans to fall in line behind Trump.
• "I don't see eye to eye perfectly with any candidate. And until now I've stayed out of it," Mace told the Associated Press. "But the time has come to unite behind our nominee."
• Haley endorsed Mace during her 2022 primary against a Trump-backed opponent.

State of play: Haley hoped for a victory or close finish in Tuesday's New Hampshire primary to give her momentum ahead of the Republicans' Feb. 24 South Carolina primary.

• Trump won the New Hampshire primary on Tuesday, followed by numerous GOP leaders in Congress calling on Haley to drop out.
• Trump leads by wide margins in South Carolina and has already picked up the backing of Republican Gov. Henry McMaster and seven of eight members of the state's Republican congressional delegation.
• Rep. Ralph Norman is the only Republican member of Congress from South Carolina who backed Haley. She's also won a number of endorsements from members of the South Carolina state legislature.

Between the lines: South Carolina, home to a conservative evangelical voter base, has swung toward Trump over the last several years.

• A private polling memo from Trump's team, obtained by Axios' Alex Thompson, showed that in a one-on-race between Trump and Haley in South Carolina, Trump had 68% support with Haley at 28%.

Zoom out: The floodgates burst open for Trump after his Iowa victory with nearly 30 new endorsements from members of Congress, governors, statewide officeholders and state legislative leaders, according to FiveThirtyEight's tracker.

• Haley picked up the endorsements of former Arkansas Gov. Asa Hutchinson and Vermont Gov. Phil Scott (R) after her third-place finish in the Iowa caucuses.
• Former presidential candidates DeSantis, Sen. Tim Scott (R-S.C.), entrepreneur Vivek Ramaswamy and North Dakota Gov. Doug Burgum endorsed Trump after ending their campaigns.
• Scott's endorsement was a slight to Haley, who appointed him to the Senate when she was governor of South Carolina in 2013.

What they're saying: Haley's campaign in a memo on Tuesday morning insisted it wasn't "going anywhere."

• "Nikki's been up against this before. No one in South Carolina thought she had a chance," Haley campaign manager Betsy Ankney wrote.
• "After Super Tuesday, we will have a very good picture of where this race stands," Ankney added.

Go deeper: Scoop: Biden-district House Republicans warm to Trump