Former Republican Sen. Jeff Flake (AZ) has called on his former colleagues to “put country over party” throughout President Donald Trump’s impeachment trial in a new op-ed for the Washington Post.

“President Trump is on trial. But in a very real sense, so are you. And so is the political party to which we belong,” Flake wrote.

Flake, who represented Arizona in the U.S. Senate from 2013 until 2019, urged his former colleagues to undergo a “simple test,” which involves questioning how former President Barack Obama would have been treated under the same circumstances.

“What if President Barack Obama had engaged in precisely the same behavior?” Flake asked rhetorically. “You would have understood with striking clarity the threat it posed, and you would have known exactly what to do.”

In the piece, Flake, who has been a frequent critic of President Trump from within the Republican Party, affirms that he believes President Trump has engaged in questionable behavior.

“But what is indefensible is echoing House Republicans who say that the president has not done anything wrong,” Flake stated. “He has.”

According to Flake, Americans have witnessed the “appalling spectacle” where House Republicans “bend to the president’s will by attempting to shift blame with the promotion of bizarre and debunked conspiracy theories.”

“If there ever was a time to put country over party, it is now,” Flake concluded. “And by putting country over party, you might just save the Grand Old Party before it’s too late.”

Earlier this year, in March, Flake suggested that he would rather a Democrat prove successful in the 2020 presidential election than President Trump.