WASHINGTON — Rumors were swirling in South Carolina early this February that Donald J. Trump would try to tear down a Republican congresswoman who had incurred his wrath.
Then Nikki Haley, his former United Nations ambassador and South Carolina’s former governor, made her move.
On Feb. 7, Ms. Haley endorsed the congresswoman, Representative Nancy Mace, jumping ahead of Mr. Trump, who backed Ms. Mace’s rival two days later. The timing of Ms. Haley’s move was widely viewed as deliberate — allowing her to exert her influence in the race without directly challenging Mr. Trump’s judgment.
“Nikki’s very smart — it’d never occur to me that she doesn’t know exactly what she’s doing,” said South Carolina’s treasurer, Curtis Loftis. “If the political winds change for President Trump, she’s prepared to be there, and this is part of that.”
Mr. Trump will be in…