Greg Sargent is
obviously confused. "Tough" questioning isn't when you examine a public figure's claims for
factual accuracy, it's when you examine them for
consistency. So if Rudy Giuliani says Bernard Kerik was a good choice to lead the NYPD, it'd be "tough" to toss up on the screen some years-old statement in which Rudy said something that was different. Asking whether or not the things he's saying are true isn't what toughness is about.
This article available online at:
http://www.theatlantic.com/politics/archive/2007/11/-tough/47071/