Atlanta ? Hardly the start he’d hoped for, Newt Gingrich’s first week as a presidential candidate has been riddled with missteps that have angered many of his fellow Republicans and exposed campaign vulnerabilities.

The former House speaker disparaged House Republicans’ Medicare proposal as “right-wing social engineering” and was all but forced to apologize after the conservative outcry. He tied himself in knots when he defended part of the Democrats’ health care law, which he says he opposes. And he refused to explain a $500,000 debt he once owed to the upscale Tiffany’s jewelry store though railing against President Barack Obama for what he calls excessive federal spending.

“He has severely damaged his campaign and his credibility,” said Debbie Dooley of Duluth, Ga., a national coordinator for the Tea Party Patriots who contended that Gingrich made things worse when he tried to explain his health care stance favoring a requirement that Americans have coverage. “If he continues with that position, for the most conservative tea party Republicans … it’s over,” she said.

Gingrich’s team says he’s not changing.

Advisers say Gingrich has repeatedly proven he can survive such troubles, and they insist there’s no need to recalibrate a campaign decades in the making.

“The base and the insiders are paying attention, and certainly Speaker Gingrich got their attention — and possibly in a bad light last week,” said Katon Dawson, a Gingrich supporter and former chairman of the South Carolina GOP. But Dawson argues that voters haven’t yet tuned in so the damage was minimal. “People have counted Newt Gingrich out on numerous occasions before at their own peril,” he said.

It was just a week ago that Gingrich officially joined the GOP presidential race.

He hopes that his tenure in the 1990s as the top Republican in the House will lend him credibility with establishment Republicans searching for a candidate in a muddled field, and that the time he spent after he left office building a grass-roots network of conservative activists will give him tea party support. He wants to be seen as the candidate of big ideas confronting the nation’s big problems. And he is looking to take a traditional path to the nomination through the early contests in Iowa, New Hampshire and South Carolina.

All that was overshadowed by fumbles this week, underscoring a major hurdle Gingrich must clear to win the nomination: himself. The missteps also renewed nagging questions about whether Gingrich has the discipline to be a White House candidate, much less president.

Gingrich’s advisers know their boss’ history of saying what’s on his mind, and they’re used to the disparagement he often stirs.

“A lesser person could not have survived the first few minutes of the onslaught,” longtime spokesman Rick Tyler said on Wednesday. “But out of the billowing smoke and dust of tweets and trivia emerged Gingrich, once again ready to lead those who won’t be intimidated and are ready to take on the challenges America faces.”

Scott Rials, a longtime Gingrich aide and a consultant on his presidential bid, said there actually is a sense of relief in the Republican’s camp.

“Listen, we knew this was coming,” he said of the criticism. “It’s like ripping the Band-Aid off. And then you move on.”

Rep. Jack Kingston, R-Ga., a Gingrich backer, said it was fortunate the rough patch occurred in the spring rather than the fall, saying: “Anyone who’s ever run for president has missteps. … He’ll recover.”