Republicans are heading Thursday to the Conservative Political Action Conference, their annual huddle on their policy agenda and conservative identity — but their party's identity, and principles, remain murky. What is the GOP — a free-market party, or one willing to bail out banks? A defense-oriented party, or one that supports old-style filibusters in protest of drone use? A balanced budget party, or a party willing to wage expensive wars? And just what is its stance on immigration? Intra-party tensions over those and other issues will take center stage at CPAC, just as — as one Politico story put it — some party leaders question the pillars of Reagan conservativism. Meanwhile, CPAC has garnered more headlines recently for its invite list, which included passé names like former Massachusetts Gov. Mitt Romney (and polarizing ones like Donald Trump) but snubbed leading lights like New Jersey Gov. Chris Christie as well as a prominent Republican gay rights group.