On Tuesday night, Rep. Mark Sanford (R-SC)—whose political career had survived scandal and just about everything else—lost the first election of his career on the heels of a scorching tweet from President Trump.

While the tweet itself likely didn’t tip the scales, Sanford’s defeat at the hands of State Rep. Katie Arrington resulted in part from his ostensibly insufficient allegiance to the president.

During a Thursday appearance on MSNBC’s Morning Joe, Sanford acknowledged that and described it as odd, especially given his consistent conservative voting record.

“We swear an allegiance to the Constitution and we pledge allegiance to the flag and what was weird about this race that I've never experienced before in any race I’ve been a part of was an allegiance question where people say are you for or against the president,” Sanford said.

He added: “I’ve never before had a question of allegiance to a person, rather than allegiance to the flag and Constitution and to a degree that’s what this race came down to.”

Reflecting on the tweet itself, Sanford wondered: “When was the last time a Republican president got into a congressional race, particularly if you’re supposedly negotiating a deal in the Far East?”

As for other candidates running across the country, Sanford said the “politics are easy: ‘Pledge allegiance to Donald Trump.’”

Doing so, however, said Sanford, would be “a mistake on a soul level.”

A rapidly diminishing cadre of Republicans are willing to criticize the president but Sanford’s loss coaxed one major figure into expressing concern about the party’s fealty to Trump.

“I mean it's almost becoming a cultish thing, isn’t it? It’s not a good place for any party to end up with a cult-like situation as it relates to a president that happens to be of, purportedly, of the same party,” retiring Sen. Bob Corker (R-TN) said Wednesday.