WASHINGTON — As Joe Walsh, the conservative talk show host and former GOP House member from a suburban Chicago district strongly considers challenging President Donald Trump, he held meetings here Thursday about a potential campaign.

Walsh was in D.C. “meeting with people who are really interested in getting behind a possible campaign,” Lucy Caldwell, who is advising Walsh, told the Chicago Sun-Times.

He is closing in on a decision to mount an insurgency bid against Trump, coming at him from the right.

In a CNN Thursday morning interview with host John Berman, Walsh, once a Trump backer, said he would decide about a run likely by Labor Day and called Trump a “horrible human being” who is “damn unfit” to be president.

“The Republican party will always, always regret the fact that they did not call this man out. Somebody has to,” Walsh said.

On Thursday, Walsh, who lives in Mundelein, kept up the Trump criticisms, saying in three tweets spread through the day: “Donald Trump has lied his entire life. In fact, his entire life is a lie. He’s a fraud”; “Not only is Trump a disaster for the country, he’s a disaster for the Republican Party. Deep down, you know that’s true”; and “He’s fit to watch TV. He’s not fit to be President.”

Walsh — or anyone — would be a long shot to wrest the nomination away from Trump since the entire Republican establishment is backing his reelection.

A Tea Party Republican elected in 2010 — only to be defeated two years later for the suburban House seat by Tammy Duckworth, now the junior senator from Illinois — Walsh in the run-up to a potential White House run has renounced the incendiary rhetoric that helped catapult him into the national spotlight and a syndicated radio show.

Walsh faces enormous hurdles in putting together a national presidential campaign, including raising millions of dollars, doing well in the early states and then navigating through the maze of state laws having to do with getting on ballots and accumulating delegates.

Caldwell said Walsh is “not contemplating this as a publicity tour” and if he jumps in, it will be “a run to win.”