Joe Walsh, a Tea Party favorite and one-term congressman from Illinois, announced on Sunday that he would challenge President Trump in the 2020 Republican primary.

“I’m going to run for president,” Walsh told ABC’s “This Week.” “I’m running because he’s unfit, somebody needs to step up and there needs to be an alternative. The country is sick of this guy’s tantrum, he’s a child.”

Communications director for the Trump campaign, Tim Murtaugh, responded to Walsh’s long-shot bid by telling ABC News, “Whatever.”

The former congressman who was elected in 2010’s Tea Party wave following President Obama’s election joins former Massachusetts Gov. Bill Weld as the only other GOP candidate opposing Trump in the primary.

Former South Carolina Gov. Mark Sanford is also weighing a run.

Walsh, 57, who now hosts a conservative talk radio show, was asked by ABC’s George Stephanopoulos about how he would defeat Trump’s in the face of his overwhelming support among Republican voters.

Referring to Trump’s backing Russian President Vladimir Putin’s denial that Russia meddled in the 2016 election over the consensus of the US intelligence agencies, Walsh said Trump’s backers “are tired of this.”

“He’s a bully and he’s a coward and somebody has to call him out. And I cannot believe nobody in our party is calling him out,” Walsh said. “But the bet, George, of my campaign is that there are a lot of Republicans who feel like I do. They’re afraid to come forward.”

Stephanopoulos also grilled Walsh over his past controversial comments on Obama’s birth certificate, calling the ex-president a Muslim, his use of ethnic slurs and being described as being “Trumpier than Trump.”

“I helped create Trump,” he replied. “That’s not an easy thing to say.”