It was Hillary Rodham Clinton, back in 2007, who said there are no do-overs in life. That is especially true for politicians. If there were, Newt Gingrich would be grasping for the opportunity.

Gingrich’s presidential hopes have always been problematic, given his controversial history. The rocky opening to his campaign has made his odds far longer. If he has learned from past mistakes, as he claimed shortly before he declared his candidacy, it was not evident in the days that followed his announcement.

What will he learn from this week?

Not for the first time in his career, Gingrich is backpedaling. But more than taking back words may be required in this case. Gingrich has undermined his candidacy not simply because, in the eyes of many Republicans, he attacked House Budget Committee Chairman Paul Ryan’s plan to overhaul Medicare. His greater problem is that he reminded people, friend and foe alike, of his inability to keep his rhetoric under control.

The opening round of the former House speaker’s presidential campaign has turned into a Gingrich apology tour. In between his stops in Iowa, Gingrich has been conducting interviews with conservative commentators in an effort to roll back what he said about Ryan’s plan on Sunday to NBC’s David Gregory on “Meet the Press.” He has also apologized to Ryan (R-Wis.) for the harm he did to the congressman, the Medicare overhaul plan — and to himself.

Gingrich’s comments were somewhere between inelegant and wrongheaded. Onetime allies on the right have come down on the side of the harsher interpretation. Gingrich has gone so far in disavowing what he said that, in an interview Tuesday night with Greta Van Susteren on Fox News, he warned Democrats not to use what he said on “Meet the Press” in any future ads.

“Any ad which quotes what I said on Sunday is a falsehood because I have said publicly those words were inaccurate and unfortunate,” he said.

The words from Gingrich on Sunday that stung the most, and from which he has been running away at every opportunity, were these: “I don’t think right-wing social engineering is any more desirable than left-wing social engineering. I don’t think imposing radical change from the right or the left is a very good way for a free society to operate.”

That set off conservatives, from Rush Limbaugh to the Wall Street Journal editorial page to William Bennett, who gave Gingrich a lecture on his radio show Monday and told him what he needed to do. “To salvage your candidacy, say you blew it,” Bennett said.

Gingrich has acted on that blunt advice, with credit to Bennett and others, and seems to have executed a reversal of his comments. He says he made a big mistake by saying what he said. He says he likes the Ryan plan. He says: “The [House] budget vote is one that I am happy to say I would have voted for, I will defend, and I’d be glad to answer any Democrat who attempts to distort what I said.” He says he continues to oppose President Obama’s health-care plan.

He has also tried to offer explanations for seemingly being so ill-prepared for such an obvious interview question on the first Sunday of his campaign. For example, he says he shouldn’t have answered “a hypothetical baloney question.” The question Gregory asked was:

“Do you think that Republicans ought to buck the public opposition and really move forward to completely change Medicare, turn it into a voucher program where you give seniors some premium support so that they can go out and buy private insurance?”

Give Gingrich credit for this: He knows the risks of tampering with Medicare, having seen what Bill Clinton and the Democrats did to him, and to Bob Dole, in the 1996 campaign after House Republicans under his leadership led an effort to restrain the growth of the program. That may be one lesson burned into his brain from that experience. So perhaps what he was doing Sunday was reminding Ryan of that history.

It also may be why he continues to harbor reservations about how the GOP has handled the rollout of the Ryan budget, because in disavowing his comments, he has not completely disavowed the idea that Republicans need to go slowly and build public support for any dramatic change in Medicare.

Ryan is the intellectual leader of the House Republicans, a role that Gingrich once played. As a private citizen, Gingrich set up his own health-care think tank, the Center for Health Transformation. He believes he knows a thing or two about health policy and health politics. He may believe he has better ideas for reforming Medicare. So factor all that into trying to understand why he answered Gregory the way he did.

Was it a sense of intellectual superiority that caused him to do it? Was it his inability to comment upon or critique the work of others without resorting to inflammatory language, as he has long done with Democrats? (The “corrupt liberal welfare state” of the 1980s and early ’90s has morphed into “Obama’s secular-socialist machine.”)

As Gingrich continued apologizing, spokesman Rick Tyler issued a statement to the Huffington Post that attacked the former speaker’s critics.

“The firefight started when the cowardly sensed weakness,” the statement said. “They fired timidly at first, then the sheep not wanting to be dropped from the establishment’s cocktail party invite list unloaded their entire clip, firing without taking aim their distortions and falsehoods.” Gingrich, he added, emerged from “the billowing smoke and dust of tweets and trivia” ready to lead “those who won’t be intimidated by the political elite.”

Candidates can recover from their mistakes, especially those made early in a campaign. Though it took him a day longer than it should have to understand the severity of his error, Gingrich is working feverishly to erase it from the public record.

But Gingrich comes with so much history that, while many Republicans may accept his apology for this misstep, they may still worry that there will be others. At some point, those become disqualifying in the eyes of voters. Whatever the cause, in seeming to attack Ryan, the new hero of the conservative intelligentsia, Gingrich has dug a very deep hole for his presidential candidacy.