Washington (CNN) Former FBI Director James Comey is urging "all who believe in this country's values" to vote for Democrats in the upcoming midterm elections.

In a tweet on Tuesday evening, Comey called the Republican-held Congress "incapable of fulfilling the Founders' design."

"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," he wrote.

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

Comey, who was fired by President Donald Trump in May 2017, also spoke out Monday against the President's comments at his joint news conference with Russian President Vladimir Putin.

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

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