CNNW The Situation Room July 17, 2012
we begin with both presidential campaigns getting down and dirty on the low road as the candidates themselves try to stick to the high road. the latest examples, killer tv ad that the obama campaign is using to welcome so-called welcome mitt romney to pennsylvania. and a top romney's surrogates complaint that the president should "learn how to be an american." let's go to our white house correspondent, dan lothian, watching all of this unfold. we've been saying it's getting ugly. >> reporter: certainly right. the fireworks today. the president was in texas attending a total of fundra...