Just days after announcing he was leaving the GOP over his disagreements with President Trump and the party’s top brass, Rep. Justin Amash, I-Mich., said on Sunday that he is not ruling out a possible White House run in 2020.

Amash, who was long the most vocal critic of Trump within the Republican Party, said on CNN’s “State of the Union” that he would consider running for president as an independent.

"I still wouldn't rule anything like that out, I believe I have to use my skills, my public influence, where it serves the country best,” Amash said. “And I believe I have to defend the Constitution in whichever way that works best.”

JUSTIN AMASH GONE FROM HOUSE FREEDOM CAUCUS AFTER SAYING TRUMP'S CONDUCT WAS 'IMPEACHABLE'

Amash did confirm that he plans to defend his congressional seat as an independent and is "very confident" he will win despite leaving the party. He faces Republican challenger Jim Lowe.

Amash announced his departure from the GOP in an op-ed published in the Washington Post on the Fourth of July. While Amash did not specifically call out Trump in his piece, he was the only member of the Republican Party to call for the president’s impeachment.

Amash said on Sunday that his issues with Trump were not the reason that he decided to leave the GOP.

“I've had concerns with the Republican Party for several years,” he said. “I've had concerns with the party system generally.”

Amash added: “When I first got to Congress I thought I could change things from the inside, but as I've spent time there I’ve seen that not only me, I don’t think there is anyone in there who can change the system.”

Trump on Thursday quickly responded to Amash’s departure in a tweet, where he called it “great news” for the GOP and labelled Amash a “total loser.”

"Great news for the Republican Party as one of the dumbest & most disloyal men in Congress is 'quitting' the Party," Trump tweeted. "No Collusion, No Obstruction! Knew he couldn’t get the nomination to run again in the Great State of Michigan. Already being challenged for his seat. A total loser!"

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Amash on Sunday brushed off Trump’s tweet – saying that lawmakers are supposed to be loyal to the Constitution, not the president.

“That’s not how people are supposed to talk to each other,” Amash said. “He thinks people owe loyalty to him, but people are elected to support the Constitution, not the president.”