Summary: What's the political fallout of President Obama's support for same-sex marriage? Plus, longtime Senator Richard Lugar, R-Ind., lost his party's primary. What does that mean for moderate republicans and incumbents? Also, the double-agent al-Qaeda plotter. Joining Gwen: Major Garrett, National Journal; John Dickerson, Slate Magazine & CBS News; Susan Davis, USA Today; Pierre Thomas, ABC News.
