Every candidate is welcome every week on my radio show, as their schedules permit. Last week, in order of appearance, came Carly Fiorina, John Kasich, Donald Trump, Marco Rubio, Chris Christie, Scott Walker, Rick Santorum, Jeb Bush, Lindsey Graham and Ted Cruz. The best communications teams take advantage of the platform, as they do of all platforms available to them where they will receive a fair hearing. The combination of a very crowded field and the intense level of interest in the race rewards those candidates who answer all questions thrown at them and come back for more.

What explains the bunching of the field, with Donald Trump indisputably atop both the national polls and key early surveys in Iowa and New Hampshire? Two things.