Political cartoon by Henry Payne of The Detroit News in Michigan and published on 30 October 2010.
Today is the day for midterm elections in the United States. Many incumbents across the country will probably be ousted and replaced. An incumbent is anyone who has an official, elected position.
To dunk means to put something into a liquid for a short time before taking it out again. Americans like to dunk their doughnuts in coffee.
In the picture, you see current Senate Majority Leader Harry Reid (Democrat from Nevada) sitting in the tank. He is expected to lose his reelection bid today. It would be the first time in five decades a Senate Majority leaders loses reelection if he does.