AUSTIN, Texas (AP) — Democrats are salivating at the prospect of flipping a wealthy Houston enclave that has been solidly Republican since sending George H.W. Bush to Congress in 1967 — the kind of race they'll have to win for any hope of retaking the House in the November midterms. But their new opportunities, here and in other states, sometimes have them going after each other instead of the Republicans, and that could spoil their chances. Aside from the normal conflicts of ambition and personality, there's a more significant Democratic rift lingering from the 2016 presidential primary between the party's...