WASHINGTON — The Republican White House race has sharpened into a three-way brawl, pitting a moderate businessman and a Tea Party firebrand against a Texas governor promising the best of both worlds.

For months, former Massachusetts governor Mitt Romney has led the polls despite conservative misgivings about his history of governing from the middle and his state health care overhaul that inspired "Obamacare."

But now he faces a major challenge from ultraconservative congresswoman Michele Bachmann, who rode a Tea Party wave to victory in Iowa's Ames Straw Poll -- seen as a key test ahead of early nominating battles.

And both could face a major challenge in longtime Texas Governor Rick Perry, a social and fiscal conservative with a strong record on the economy, whose entry into the race on Saturday rained on Bachmann's Iowa parade.