Every candidate has weaknesses, the political truism tells us. But in the case of Newt Gingrich his most serious ones are entirely self-inflicted. There are five that have stood out this week.

First, he can’t use his current wife as other candidates use their only wives. Callista is essentially being kept under wraps — and for good reason. Sooner or later someone is going to ask if she regrets breaking up Gingrich’s second marriage or how she’d feel if someone younger than her came along to snatch her husband. She gave a CBN interview that was hardly grueling. But even the “good” parts are problematic. You don’t know whether to laugh or cry when she says, “I have always been a very spiritual person. . . . I start each day with a prayer and I pray throughout the day and I pray at the end of the day.” To be blunt, she is a walking reminder of his infidelity and would, if her spouse wins, be the only homewrecking ( publicly known, at any rate) first lady we’ve had.

Second, Gingrich has ruined his defense that he is a “changed” man. His repeated attacks on Rep. Paul Ryan (R-Wis.) and his class warfare attack on Mitt Romney, and his notions about child janitors and the “invented” Palestinians reveal him to be the same undisciplined and egomaniacal figure he’s always been. It is his inability or unwillingness to address his politically debilitating flaws that resulted in an extraordinary “anybody but Gingrich” endorsement by the National Review editorial board:

We fear that to nominate former Speaker Newt Gingrich, the frontrunner in the polls, would be to blow this opportunity [to retake the White House]. . . . .

His character flaws — his impulsiveness, his grandiosity, his weakness for half-baked (and not especially conservative) ideas — made him a poor Speaker of the House. Again and again he combined incendiary rhetoric with irresolute action, bringing Republicans all the political costs of a hardline position without actually taking one. Again and again he put his own interests above those of the causes he championed in public. . . .

At the moment we think it important to urge Republicans to have the good sense to reject a hasty marriage to Gingrich, which would risk dissolving in acrimony.

Third, his electability problem is more obvious now that he is a legitimate contender for the nomination. In the RealClearPolitics poll average, President Obama leads Romney by less than 2 percentage points, well within the margin of error; he leads Gingrich by more than 8 percentage points. If Republicans want to win the White House more than anything else, this is a serious challenge for Gingrich.

Fourth, it took Gingrich to make Romney a sympathetic figure. Suddenly, Romney is the one fending off attacks from the left. Now Romney is scraping for votes. The air of inevitability surrounding Romney that rankled conservatives is gone, and now he’s having to prove he’s a determined competitor. Romney never got as much help from the conservative media as when Gingrich attacked him for — gasp! — being a capitalist.

And fifth, Gingrich, either because he mismanaged his funds or because he arrogantly assumed he didn’t need to, is not running TV ads in Iowa or New Hampshire. His opponents are, and their ads are helping to push Gingrich’s negatives up. His campaign claims to have raised $4 million in the first half of the fourth quarter of 2011, but so far there is no sign that money is going toward anything productive.

Gingrich has always been his own worst enemy, but in the last week or so we’ve seen just what a toll his character takes and how it deprives him of some of the tools other candidates can use. They have biting ads, prominent surrogates and helpful wives. Gingrich has Gingrich and Callista. You see the problem.