President Obama traveled in the presidential limo with his dog, Bo. Adviser David Axelrod tweeted this photo from the White House Flickr account to tweak the Romney campaign. Pete Souza/White House hide caption toggle caption Pete Souza/White House Opinion It's All Politics Campaigns Embrace Twitter: Who Let The Snark Out? January 31, 2012 Twitter has become the latest medium for campaign spin. It's a stream of barbs over debates, crowd estimates and ad wars. And even the candidates' dogs are not off-limits.