(CNN)President Donald Trump's decision Tuesday to go after an incumbent Republican congressman who had previously criticized him flouted the advice of allies who suggested he stay out of the race.
Rep. Mark Sanford, a rare conservative member who was also critical of the President, lost his GOP primary on Tuesday to Katie Arrington, a South Carolina state representative who made Sanford's negative comments about Trump the focus of her campaign.
Just hours before the polls closed in Sanford's district, Trump slammed the former South Carolina governor on Twitter and endorsed Arrington -- much to the dismay of the House Freedom Caucus, of which Sanford is a member. In a rare dissent from the President, Rep. Mark Meadows issued a statement shortly after Trump's tweet that reaffirmed he was "very supportive" of Sanford's re-election bid.
One White House aide said Trump's disdain for Sanford should not have come as a surprise to the conservatives now protesting the President's intervention in his primary.
"Sanford is the worst and has been against the President and our policies from Day One," the aide said. "It should be no surprise to the Freedom Caucus that the President came out against him in the primary."
The aide argued Sanford "might have lost anyways" because Trump withheld his shot at Sanford until late in the afternoon on Tuesday.
"I don't think the timing was deliberate. (Trump) tweets when he wants to tweet," the White House aide added.
The President's attack on Sanford came as he and senior aides were traveling Tuesday from Singapore to Washington, returning from a summit with North Korean leader Kim Jong Un.
Hours after Sanford's electoral fate was sealed, Trump took a victory lap on Twitter, claiming his advisers had attempted to prevent him from weighing in on the race.
"My political representatives didn't want me to get involved in the Mark Sanford primary thinking that Sanford would easily win - but with a few hours left I felt that Katie was such a good candidate, and Sanford was so bad, I had to give it a shot. Congrats to Katie Arrington!" Trump tweeted Wednesday morning.
Arrington narrowly locked Sanford out of a runoff by getting slightly more than 50% of the primary vote. But because just a few hundred ballots denied Sanford the opportunity to compete in a run-off, one senior White House official said Trump's tweet likely played a decisive role in the race's outcome, despite the fact that the President did not send it until late in the afternoon on Tuesday.
The senior White House official said Trump typically has a meeting each week, during which his political team presents him with updates on the electoral landscape for Republicans. But, because Trump had been so busy preparing for his summit this week with North Korean leader Kim Jong Un, he did not have his political meeting for the past two weeks. the senior official said.
Sanford's vulnerability in the GOP primary did not become apparent until recently, the senior official added, so Trump's political team did not even have time to brief him on the prospect that Arrington could win.
"All of this happened when he was basically offline for us," the senior official said. "So whatever inputs he's talking about, he's not talking about his political team."
But two sources familiar with the situation said Trump was indeed referring to his "internal team" when he blamed nameless "representatives" for trying to keep him from going after Sanford.
An administration official said both White House aides and members of the House Freedom Caucus made unsuccessful attempts to persuade Trump to hold his fire before Tuesday's primary.
Conservative lawmakers and aides are mourning Sanford's electoral loss this week and questioning why Trump chose to go after a member who had voted for his priorities.
"It's a blow," said one senior Freedom Caucus aide. "Sanford is a widely respected member of (the House Freedom Caucus) and it will hurt us to lose him."
Two other congressional sources said some Freedom Caucus members were angry and confused when they saw Trump had come out against Sanford. Several had privately suggested Trump stay out of the race despite his personal animosity toward the South Carolina conservative.