Khizr Khan, the father of the late American war hero U.S. Army Capt. Humayun Khan, has challenged the Republican party for its support of Donald Trump, urging Senate Majority Leader Mitch McConnell and House Speaker Paul Ryan to "repudiate" the GOP nominee. In an interview with MSNBC on Friday, Khan called it a "moral imperative" for the two to stand up to Trump. "If your candidate wins and he governs the way he has campaigned, my country, this country, will have constitutional crises [like] never before," Khan warned. Calling Trump's possible leadership a "threat to our democracy," Khan begged McConnell and Ryan not to be deterred by "political consequences" and to put an end to Trump's "schoolyard bullying." Khan, whose Muslim-American son died fighting for the U.S. in Iraq, delivered an epic speech alongside his wife at the DNC earlier this week in which he railed against Trump for his anti-Muslim rhetoric and asked the Republican candidate if he'd ever even read the U.S. Constitution. Khan's speech was hailed as the most powerful speech at the Democratic convention, though Trump's reaction to it was simply: "I'd like to hear his wife say something."