WASHINGTON - Former House Speaker Newt Gingrich came from behind to win the Republican presidential nomination contest in South Carolina Saturday, defeating former Massachusetts Governor Mitt Romney, the front-runner, by double digits, results showed.

With 99 percent of precincts reporting, television reports said Gingrich took 40 percent of the votes in the primary in South of the country, with Romney a distant second at 28 percent.

Former Senator Rick Santorum of Pennsylvania was third with 17 percent and Congressman Ron Paul of Texas fourth with 13 percent. Both pledged to remain in the race. CNN exit polling indicated South Carolina voters see Gingrich as more electable than Romney, based on his debate performances.

It was a striking development in a months-long Republican nominating contest that has seen the restive base of conservative voters ping-pong among the alternatives to the party establishment’s favorite, Romney.

With late-night tallies showing Gingrich beating Romney by 12 percentage points, it was no small win. Exit polls showed Gingrich had done it with a formidable coalition of groups that have resisted Romney’s candidacy all election season long: evangelical Christians, Tea Party movement supporters and those who call themselves “very conservative.” Gingrich now heads to Florida, where he faces a daunting test in seeking to capitalize on his new status as the candidate who poses a singular, insurgent threat to Romney. He used his victory speech to cast himself as the champion of the party’s anti-establishment wing, reprising his popular castigation of the news media and other “elites” while keeping his focus on the defeat of President Barack Obama in the November elections.

Standing beside his wife, Callista, as he addressed an exuberant crowd in Columbia, Gingrich attributed his victory to “something very fundamental that I wish the powers that be in the news media will take seriously: The American people feel that they have elites who have been trying for a half-century to force us to quit being American.” “People completely misunderstand what’s going on. It’s not that I’m a good debater. It’s that I articulate the deepest-felt values of the American people,” Gingrich said.