Justin Amash on Trump: 'We must elect someone who will restore respect for our Constitution'

WASHINGTON -- Rep. Justin Amash, Republican turned independent congressman from Michigan, tweeted on Friday that, “in 2020, we must elect someone who will restore respect for our Constitution and each other,” and said President Donald Trump "appears increasingly unstable."

Amash, a vocal Trump critic, announced in an op-ed July 4 that he was leaving the GOP. He remains in the House of Representatives as an independent.

Prior to leaving the GOP, he was the only Republican member of Congress to come out in favor of impeaching Trump in light of the Mueller report's findings and conclusions.

In his tweet Friday, it’s unclear if Amash was referring to the possibility of a successful challenge to Trump for the GOP nomination, or, rather, a possible Trump loss in the general election to a Democrat or even to a third-party candidate.

Trump is already facing one official challenger in the GOP primary. Former Massachusetts Gov. Bill Weld announced his White House bid in April.

Additionally, former GOP congressman turned conservative radio host Joe Walsh and former Rep. Mark Sanford, R-S.C., have publicly discussed the possibility of challenging Trump for the GOP nomination.

They have both said they intend to make a decision by Labor Day.

More: Joe Walsh and the other Republicans who may challenge Trump in the 2020 primaries

The Washington Post also reported that Jeff Flake, a former Arizona senator, said he has taken numerous recruitment calls in recent days from GOP donors who are eager for an alternative to Trump, and that, according to an adviser, former Ohio governor John Kasich will head to New Hampshire next month to “take a look at things” after experiencing “an increase” in overtures this summer.

Furthermore, Amash himself hasn’t completely ruled out a third-party bid for president. Appearing on CNN in July soon after leaving the GOP, when asked if he would run for the highest office in the land, he said "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, and I believe I have to defend the Constitution in whichever way works best.”

“And if that means doing something else then I do that. But I feel confident about running in my district. I feel a close tie to my community. I care a lot about my community; I want to represent them in Congress," responded the 39-year-old congressman.

Amash’s tweet also comes as he faces multiple challengers for his congressional seat.

Five Republicans and five Democrats have announced they are seeking their party’s nomination in the August 2020 primary in Amash's Michigan district.

In June, Amash and Donald Trump Jr., the president's eledest son, duked it out on Twitter after Trump Jr. retweeted Michigan poll numbers showing Amash trailing challenger Jim Lower.

Amash responded to Trump with a reference to comments Trump Jr. had made in emails to British publicist Rob Goldstone. "If it's what you say I love it especially later in the summer," Trump Jr. had written at the time, regarding potentially damaging information about Hillary Clinton.

Amash used that line verbatim to reply to Trump's threat.

This article originally appeared on USA TODAY: Justin Amash: Donald Trump 'appears increasingly unstable'