Nixzmary Brown and Matt Long never met. Even so, they have a lot in common as victims of government’s failure to enforce the law.

Nixzmary was killed by her stepfather last week, following years of abuse that makes Abu Ghraib and Guantanamo sound like summer camp. There was plenty of evidence over the last year that the seven year-old had been a human punching bag, but city officials failed to seek a warrant for access to her apartment. Suspicious bruises, malnourishment and unexplained absence from school apparently weren’t sufficient signals of distress. Chronic absence from school should itself be enough to trigger a warrant application automatically.

Around the time last month that Nixzmary’s truancy should have sounded a loud alarm, Matt Long suffered critical injuries when he was hit by a charter bus while riding his bike to work as a firefighter during the transit workers’ selfish strike. Mr. Long was on his bike only because subways and buses weren’t running, even as transit union chief Roger Toussaint was shuttling between meetings in a chauffeur-drive SUV equipped with a siren.

Mr. Toussaint should have been in jail, where perhaps he would have decided the strike wasn’t worth his liberty. Under the state’s Taylor Law, which rendered the transit strike illegal, a judge could have ordered Mr. Toussaint and other union leaders jailed immediately. In fact, the strike only ended an hour before a judge was set to send Mr. Toussaint to jail on the third day of the walkout.

Government leaders worried that putting Mr. Toussaint and his cronies in jail would make them martyrs. Perhaps. But there is also the chance that jail time would have ended the strike much sooner. We simply will never know. We do know there is something especially tragic about the fact that Firefighter Long was nearly killed because transit workers went on strike just three days after their contract expired, given that his fellow firefighters recently served the public for well over four years without a new contract in place.

Patience has its place, and protecting the public is no place for dillydallying. The transit strike was an obvious hazard to public safety, just as Nixzmary was suffering obvious signs of abuse. Child protection workers should have instantly sought a warrant for Nixzmary’s home, once she disappeared from school last month, just days after her teachers noticed a bruise on her eye. Her parents claimed she fell, and a doctor supposedly bought the lie. But the black eye was just a piece of the puzzle.

With no excuse, Nixzmary stopped showing up at school. She didn’t claim to be out sick or away visiting relatives. She was AWOL. And when city officials went to check on her, Nixzmary’s stepfather shut them out.The red flags were burgundy, and should have instantly set off an automatic series of events to find the girl – including the legal right to barge into her apartment unannounced.

Officials had the ability to seek a warrant, and Mayor Bloomberg says there was some discussion about going to court for permission to knock down her door if necessary. The problem here is that there was need for discussion. Chronic unexplained absence from school is especially troubling because the absence prevents teachers and trained guidance counselors from observing evidence of abuse. Such a clear sign that something is at the very least amiss should automatically prompt a warrant application. In fact, a judge should immediately be assigned to the Department of Education’s Tweed headquarters specifically to handle these cases and make sure they are handled quickly.

The tragic common denominator linking Nixzmary Brown and Matt Long is government overthinking. And we are already seeing more overthinking as lawmakers rush to win publicity from Nixzmary’s death by proposing new laws to toughen punishment for child abusers. The laws are tough enough.

Officials need to learn how to use tools already at their disposal before we start entertaining proposals for new laws that will simply create more opportunities for missed opportunities.

A former deputy attorney general, James Comey, proved how effective enforcement can be while working in the late 1990s as a federal prosecutor in Richmond, Va. Gun crime was out of control and state laws were too lax. Instead of wasting time and resources to make new laws, Mr. Comey found a way to bring gun cases into federal court where existing laws were tough – the punishment for gun possession was five years in prison. Billboards went up all over Richmond as part of Project Exile, warning that illegal possession of a gun would lead to exile in federal prison. The plan worked.

Perhaps parents inclined to abuse their children will punch a wall instead of a person if they can’t cover up the abuse simply by keeping the kids out of school until the bruises heal. Parents should be told that if their children are missing from school for a specific number of days – a week, 10 days, whatever the experts decide – then the school system will automatically seek a warrant for police and child welfare agents to enter their home and figure out what’s going on.

The law is there. It’s time to use it. Nixzmary Brown won’t be the last “child known to the system” to die at the hands of an abusive parent. And Firefighter Long won’t be the last bike rider to be hit by a bus making a wide turn. But in both cases, tragedy might have been averted if only government had used the reasonable tools available to enforce – or at least try enforcing – the law. The system failed Firefighter Long the moment Mr. Toussaint left the union hall a free man after authorizing the strike. The system failed Nixzmary the moment anyone had to ask the question, “Should we get a warrant?”

Mr. Goldin writes a weekly political column for The New York Sun.