Former FBI Director James Comey tweeted late Tuesday night that "all who believe in this country's values must vote for Democrats this fall."

Comey blamed the Republicans in Congress for proving "incapable of fulfilling the Founders' design that ‘Ambition must … counteract ambition."

"Policy differences don't matter right now. History has its eyes on us," Comey added.

This Republican Congress has proven incapable of fulfilling the Founders’ design that "Ambition must … counteract ambition." All who believe in this country’s values must vote for Democrats this fall. Policy differences don’t matter right now. History has its eyes on us. — James Comey (@Comey) July 18, 2018

A day earlier, Comey slammed President Donald Trump for trusting Russian President Vladimir Putin over American intelligence agencies on whether Russia interfered in the U.S.'s 2016 elections.

"This was the day an American president stood on foreign soil next to a murderous lying thug and refused to back his own country," Comey said. "Patriots need to stand up and reject the behavior of this president."

In late June, Comey said he wanted Democrats to nominate a candidate in 2020 who could appeal to the "great middle."

"The rhythm of history, of American history, tells us that eventually, the American people in their great mass will tire of him and come to realize that he threatens what is essentially America, which is our values," he said in a podcast interview.

Trump fired Comey in May 2017, spurring a series of events that led to the appointment of special counsel Robert Mueller to lead the Justice Department's investigation into Russian interference in the 2016 election. Since being fired, Comey has compared Trump's leadership to a Mafia boss and called him "morally unfit" to hold the presidency. Trump responded by calling Comey an "untruthful slime ball" and the worst FBI leader ever.

Comey has also been criticized by others for his actions as FBI director and the decisions in the investigation of Hillary Clinton's private email server, with many Democrats—including Clinton—blaming him for her election loss. The Justice Department inspector general found Comey made serious errors in judgment throughout the probe, including his late-October letter to Congress announcing a re-opening of the investigation.