The latest GOP poll, with Trump up 20, is nearly meaningless

Donald Trump is at 36 percent in a recent poll, and Philip Bump at the Washington Post has a piece up about why that is important.

But here's the thing: the poll is not very important at all, for many reasons.

1) It's a national poll — there's no such thing as a national primary.

National polls are helpful very early in the primary season. In 2008, 59 days out, Rudy Giuliani was easily in first place nationwide, with double-digit leads on McCain, Romney and Huckabee. He went nowhere. In 2012, Cain was the leader nationally, but Romney was the leader in New Hampshire. It's a messy picture historically, but leading in national polls does not correlate very strongly with winning Iowa or New Hampshire, but winning Iowa and New Hampshire strongly influence your performance in the national polls.