Not a moment too soon, Pollster.com's Mark Blumenthal provides some important context on that new ARG poll showing Hillary with a 15-point Iowa lead. Short version: Polling on a holiday travel weekend is rare and dodgy, and likely to underrepresent younger, better-educated voters--in other words, voters who tend to favor Obama and whose absence from a survey would probably aid Hillary Clinton. Seems best to wait for post-Christmas polling, which is surely being conducted now and will likely appear by the weekend.

--Michael Crowley