Gingrich and Romney Trade Jabs as G.O.P. Race Rolls On

By JEFF ZELENY and JIM RUTENBERG
NYT

TAMPA, Fla. — Facing a restive Republican Party and a resurgent Newt Gingrich, Mitt Romney shifted course on Sunday and agreed to release his tax returns this week, as the two candidates and their allies buckled in for a combative and unpredictable new phase of the presidential nominating campaign.

Not 24 hours after Mr. Gingrich’s victory in the South Carolina primary, the two camps were trading charges over the Congressional ethics inquiry on Mr. Gingrich in the 1990s, over Mr. Romney’s tax returns and over whether Mr. Gingrich’s consulting work for the government-sponsored mortgage lender Freddie Mac amounted to lobbying.

Their immediate battleground is Florida, which will hold its primary in eight days. But their intensifying duel was also shaping up as a proxy battle in the fight between the Republican Party’s establishment wing — in favor of Mr. Romney — and a grass-roots insurgency that, for now at least, seems to be coalescing around Mr. Gingrich as a no-holds-barred opponent to President Obama in the fall.

“He’s done something that most people don’t really understand,” said Mallory Factor, a Republican activist based in South Carolina who organizes a weekly meeting of conservative donors in New York City. “He has channeled the frustration of the Republican base and independents.”

(More here.)