If you haven't yet seen it, you really need to watch Thursday night's Democratic convention speech by Khizr Khan, the father of Army Cpt. Humayun Khan, a Muslim immigrant who was killed in action in Iraq in 2004 while protecting his unit from a car bomb. Khan demanded to know whether Donald Trump had even read the Constitution, pulled out his pocket copy, and offered to lend it to Trump. I watched this moment live and was awed by it.