Ms. Tanqueray is obeying the speed limit and paying close attention to the road as it bends and twists along the Schuylkill. She's driving fine, even stopping to let a pedestrian cross. Fiddling with his cell phone, Mr. Mountain Dew is swerving and speeding to see how well his ride handles the curves. He loses his grip on the steering wheel, hits a puddle, hydroplanes over the dividing line and collides with Ms. Tanqueray's car. Airbags deploy, but nobody's seriously hurt.

When the cops arrive, who's getting charged:

a) The woman with enough gin in her system to cross the breathalyzer's red line, or

b) The person who's really to blame?

Regardless of reality, the accident was her fault. With no witnesses around, the guy who ran into her isn't about to take the fall. Make no mistake about it, this happens. Often.

Well, good people, that scenario summarizes the inherent injustice of America's drunk-driving laws. Even when not to blame for a collision, the person who blows a .08 goes down. It's an easy investigation. It's a case quickly closed.

This is not to say I condone getting behind the wheel when you're drunk. Don't. It's wrong. And because it's wrong, we can tolerate the injustice and feel no sympathy for a person who, by having bad luck and timing, got caught doing something they shouldn't have been doing. Everybody's better off with them off the road, right?

If we can all agree on that, then let's take it a step further.

As in, it's time to take the lessons learned from sobriety checkpoints and parlay them into roadside ambushes for people driving around town with guns in their car or walking around town with one tucked in their waistband.

If the U.S. Supreme Court says it's legal for police to make people prove they aren't drunk without probable cause, then they need to be empowered to make people prove they're not illegally armed, too.

Police should be permitted to pick corners in known hot spots, stop any car passing by and search it for a weapon. They should also be permitted to pat everybody in that car down, and to frisk anybody who has the dumb luck of walking by at the wrong time. Should they cry foul? Well, if it takes a lawsuit against Philadelphia to become a test case, what better city is there to put on a national stage in the fight against senseless violence?

Like with Ms. Tanqueray, we need to accept the fact that driving while armed is as, if not more, dangerous than driving while intoxicated, and that getting an illegal gun off the streets is as important as cuffing a drunk driver.

We needn't get all caught up in how New York City cops were found to disproportionately target blacks and Hispanics when they were given the green light to conduct stop-and-frisks a few years back. That system was ripe for abuse; the unfettered right to pick and choose whom to stop makes it easy for someone's bias or racist tendencies to slip in.

But it isn't about racial profiling or civil rights when you stop every last person who drives up to an intersection, as could be done at an Illegal Gun Checkpoint. To say it's wrong would be the equivalent of maintaining that a drunk who is obeying most traffic regulations shouldn't be pulled over, or charged if an accident occurs.

Would establishing such a system erode some of our civil rights? No more than the DUI stops did, so long as police remain required to announce where they'll be holding such stops. It's simply the right thing to do, and the right time to do it.

Just look back at the night Solomon Montgomery allegedly burst into Pat's Cafe wielding a sawed-off shotgun, demanded money from the patrons and fatally shot Officer Gary Skerski through the neck so he could flee the scene.

With one of their respected peers dead, officers fanned out across the city looking for anybody who matched the suspect's description.

During a manhunt that included countless traffic stops, they searched potential suspects and their vehicles. During at least four of those stops, they found illegal weapons. Illegal weapons that probably would have never been seized hadn't a cop been killed. Illegal weapons that probably would have been used in the commission of another crime, on another day.

Does the seizure of four guns make Philadelphia any safer? Marginally, at best. But if they paved the way for police officers to be armed with another weapon against the violence plaguing the city, they'd be the most important criminal seizures in our history.