Here's a classic example of reactive law-making. The Chicago City Council's transportation committee has approved an ordinance that would significantly increase fines for motorists who fail to stop at stop signs. The penalty for a first offense would climb from $90 to $100 and reach as high as $1,000, plus community service, for repeat offenders.

The ordinance was prompted by the death of a 4-year-old girl who was killed by a Lexus whose driver blew through a stop sign.

We've seen things like this before. A terrible tragedy occurs that involves a child. Legislators naturally want to do something about it and feel that they are in a position to do something about it. They pass a law and name it for the victim.

Is that really the best way to set public policy?

It may well be that Chicago needs to crack down more on people willfully ignoring stop signs. Certainly here in Washington, DC, drivers seem to think that stop signs and red lights are merely suggestions. (Pedestrians, too, by the way.)

But it seems as if Chicago already has ordinances -- and penalties -- in place to address this issue. Will increasing the size of fines really make a difference?

No one would argue that a young girl's life is not worth a little more congestion in the courts. But that's the problem with this type of legislation. No one can argue against little girls and no one takes seriously the possibly negative impact of a quick solution.

Let's think about the increase in the penalty for a first offense. A $10 increase may not sound too impressive. But in Chicago, if your fine is $100, you have to show up in court. "You'll probably end up with another 20,000 or so individuals coming to Traffic Court,' said Robert Evans, commander of the Chicago Police Department's Traffic Section. "When people see the seriousness and that they have to go to court, it'll make them think twice about running that stop sign."

Well, maybe so. But I'm guessing (sorry, no real reporting here) that this means that the cop also has to show up in court. Is this likely to make police on the beat a) more or b) less likely to issue tickets when people ignore stop signs?

Let's say it makes them more likely. Just for the sake of argument. That means that Evans' estimate is low and that the courts are going to have to handle an increase of more than 20,000 cases a year.

These are just the potential problems that are implicit in the Sun-Times story about the proposed ordinance. As we all know, or should know, the law of unintended consequences means that there will be further unintended and unforeseen consequences to such laws. Acting in haste and out of emotion is a poor way to puzzle out what all the consequences may be.