By Gilbert Garcia

October 14, 2014 | Updated: October 15, 2014 10:24am

Cinderella's stepsisters learned it the hard way. If the slipper doesn't fit, there aren't enough shoehorns in the world to help you wedge someone's foot into it.

These days, the campaigns of Nico LaHood and Will Hurd are trying to put some ill-fitting shoes on the feet of their opponents, and the strain is all too evident.

When LaHood, a local defense lawyer, challenged Bexar County District Attorney Susan Reed in 2010, the dominant message of his campaign was that Reed — in her zeal to adopt a hard-nosed “one-size-fits-all” approach to crime — had done little to relieve the revolving-door effect of recidivism.

Although LaHood lost the election, it was a message that resonated with many voters, because, aside from concerns about favoritism, the biggest knock on Reed over her 16 years in office has been that she's too Draconian and prone to shoot from the hip (as when she responded to the 2008 killing of beloved local restaurateur Viola Barrios by saying, with regard to the 18-year-old suspect, “I'd like to go string this guy up myself.”).

This year, LaHood is trying to out-Reed Reed, by downplaying the restorative-justice appeals of four years ago in favor of relentless accusations that Reed has been too easy on sexual predators.

Make no mistake, LaHood raised the issue four years ago, with a TV ad telling us, “In Bexar County, when child predators get caught and charged with indecency with a child, or sexual assault, Susan Reed couldn't get a conviction.”

That ad, however, was folded into a broader theme: that Reed was ineffective and unwise in the way she marshaled her office's resources.

This year, there's a difference in tone and emphasis, as LaHood — bolstered by nearly $700,000 in campaign funds from Corpus Christi personal-injury lawyer Thomas J. Henry — has essentially turned his rematch with Reed into a one-issue race.

That became particularly obvious last week during a television debate between the two candidates on “Texas Week” with Rick Casey. When LaHood argued that child abuse cases have more than doubled in Bexar County since Reed took office, she said his numbers were “misleading to the public,” because, among the nearly 6,000 “abuse and neglect” cases last year cited by LaHood, Child Protective Services only referred 800 to her office.

We're all used to seeing manufactured, camera-ready anger from politicians, but when Reed stared down LaHood, pointed her finger at him and said, “No, you let ME finish, young man,” that was genuine rage.

It's worth remembering that Reed is the same DA who has gone to the extreme lengths of ordering all registered sex offenders in the county to sign a statement promising not to participate in any Halloween activities. For all her much-documented flaws, the notion that Reed is indifferent on the issue of sexual abuse simply doesn't ring true.

In the case of Hurd — the former CIA officer turned GOP congressional candidate — the biggest crimes against credibility have not come from the candidate himself but from his deep-pocketed surrogates.

Pete Gallego, a first-term District 23 representative from Alpine, is a mild-mannered moderate who prides himself on working across party lines.

To put things in perspective, the National Journal gave him a 56 percent rating on their liberal scale, compared to a 74 for Joaquin Castro and 79 for Lloyd Doggett. By that rating system, Gallego and Laredo-based Rep. Henry Cuellar are by far the most conservative Texas Democrats in Congress.

Even though Gallego wasn't in Congress when the Affordable Care Act passed — and he has called for modifications to the law — an ad by the pro-Hurd Congressional Leadership Fund tags him as “Wrong on Obamacare, too liberal for Texas.”

Hurd's own campaign has driven home that point, with an ad featuring citizen testimonials asserting that “Gallego put us deeper into debt” and “He's a career politician who supported Obamacare.”

A recent ad by the National Republican Congressional Committee charges that “radical environmentalists” put Gallego in office, and now “they're messing with Texas.”

Keep trying to force that size 8 shoe on a size 10 foot, and see how it works for you.