An email from the Obama campaign says an estimated 18,500 people attended the Obama-Oprah event in Des Moines today. I'll be attending the New Hampshire rally tomorrow night.

Update: A cocky Obama adviser tells Ambinder that Chelsea Clinton's appearance in Iowa today was "kind of like bringing a knife to a bazooka fight." Careful now--bragging is bad karma! Let the press say it for you...

--Michael Crowley