WASHINGTON (AP) — The tea party movement's best remaining hope for picking off an incumbent Republican in the Senate has boiled down to one state, Indiana, where six-term Sen. Richard Lugar still faces a challenge from the right.Polls show Lugar is vulnerable, despite decades as one of the Senate's foreign policy experts. But the tea party candidate challenging him in the GOP primary, state treasurer Richard Mourdock, lacks Lugar's heft and name recognition.It looked for a time as if three longtime Senate moderates — Orrin Hatch of Utah, Olympia Snowe of Maine and Lugar — were in danger of challenges from the right. But the upstart campaigns in Utah and Maine have fizzled.That leaves Mourdock, running for months with little attention, as the tea party's best shot in the Senate.