Former president Bill Clinton and Hillary Clinton at New York City Mayor Bill de Blasio’s inauguration. (Carlo Allegri/Reuters)

Hillary Clinton may have a Mitt Romney problem. It is not merely a function of her wealth and isolation from the real world. (She and Bill Clinton are treated like royalty and operate behind a phalanx of security.) Rather, she is uniquely unable to criticize potential opponents on points on which they may be the most vulnerable.

The woman who thinks politics, like love, is about never having to say you’re sorry and who collects scandals like little old ladies accumulate cats will find it dicey to go after Gov. Chris Christie on the bridge scandal. The woman who went after the White House travel office, who opposed the surge to get the 2008 nomination and who ran a brutal campaign against Barack Obama in 2008 will be hard-pressed to call Christie a “bully.” (And she risks being portrayed as insufficiently tough for the job if she complains that Christie yells at the media or goes toe-to-toe with the opposing party’s legislative leadership.) As an aside, it is jaw-dropping that the mainstream media consider the bridge scandal (mischief by underlings in creating a traffic jam) disqualifying but Hillary Clinton’s negligence (at the very least) and lack of candor (at the very worst) about an attack on a U.S. diplomatic mission in Benghazi, Libya, in which four Americans died, a non-issue.

Moving on to other potential Republican nominees, the woman who has not a single foreign policy accomplishment may find it tough to claim someone such as Sen. Marco Rubio (R-Fla.) hasn’t accomplished much. His speeches stack up well against hers, and he at least hasn’t presided over a series of policy debacles.

Arguments that might be made convincingly by other Dems don’t work for her. Against Rep. Paul Ryan (R-Wis.), will she really be able to say she’s the best one to put political animosities aside and get things done? (Obama beat her on 2008 by making the case she would carry decades of partisan baggage into the Oval Office.)

Any GOP governor can claim outsider status (as did Obama) against Clinton, who has been on the taxpayers’ payroll or living in the White House for 20 years (not including her work as a staffer on the Watergate hearings).

A more dynamic and engaging campaigner might make a candidate such as Wisconsin Gov. Scott Walker seem dull, but next to Clinton, Walker is downright folksy. A more easy-going and self-deprecating candidate might make Sen. Rand Paul (R-Ky.) look thin-skinned, but not Clinton.

In other words, Romney felt constrained in going after the president on Obamacare and was personally unable to capture the lower- and middle-class voters most hurt by Obama’s policies. Likewise, Clinton’s life experience and persona make her less able to go up against a big personality, such as Christie, an accomplishment-light Rubio, deal-maker Ryan, outsider Louisiana Gov. Bobby Jindal, man-of-the-people Texas Gov. Rick Perry or even an easily piqued senator.

This is not to say she won’t win the nomination. Her troubles, rather, lurk in the general election. And it’s not to say she can’t beat Republican contenders. But it is easy to see how a candidate with a different profile would have an easier time of it. An outsider, a fresher-face, a more accomplished figure, a less regal figure or a candidate who didn’t run on the individual mandate in 2008 would, I think, have fewer constraints and more options in taking on a Republican nominee. Whoever that nominee is, he or she will paint Clinton as the essence of what is wrong with D.C. — a blame passer, a partisan warrior, an expert at failing upward, a pol who got rich off her public service and a dogmatic liberal who championed the worst policy idea in decades. No wonder Republicans are optimistic about 2016.