Some of the worst policy changes in modern history have happened when lawmakers have let emotions and anecdotes dominate debate rather than facts and figures — actual evidence. Consider the short-lived “assault weapons” ban of 1994, nearly any law named after a deceased child, or President Trump enacting steel and aluminum tariffs.

Passions are understandably running hot after the appalling Florida school shooting on Feb. 14. In its wake, both conservatives and liberals have jumped to heavy-handed policy conclusions that would be ineffective.

Liberals are calling for an unfeasible ban on “assault weapons," using their favored misnomer for America's most popular semi-automatic rifles. Many conservatives, meanwhile, are calling on government to pay for armed security guards and metal detectors in every school. That would be both ruinously expensive and would not work. High schools already feel like prisons, and TSA-style security would make them worse.

The murder of school children is a terrible calamity, but schools overall are incredibly safe, both in terms of mass shootings and of everyday crime. The experiences of students traumatized at a mass shooting need to be heard, but neither their ordeal nor their fear and anger turn them into policy experts. Passion should not be allowed to trump reason. Anecdotes should not displace facts. The perspectives of victims are important and should be heard, but students deserve sympathy, not carte blanche to dictate the trampling on fellow citizens' rights.

There’s an instructive parallel in the judicial system. We entrust decisions on sentencing criminals to neutral judges, not to victims, their families, or their outraged neighbors. It's the difference between a court and a lynch mob. Judges and juries weigh evidence and testimony from plaintiffs and defendants. Politicians should weigh all available evidence in the policy debate that naturally follows an event such as the Parkland, Fla., shooting. Constituents from across the political spectrum will supply it. Only then should policy prescriptions be drawn up.

The gun debate is always revived after a mass shooting, as it should be, but that is also when fear and anger are at a peak. Politicians should not let debate die away as Parkland fades into the past. They should shape sensible policy with cool deliberation. They should regard the gradual abating of passions as an opportunity to do their duty, not as a chance to sidestep because no one is thinking about the issue — until the next mass murder. Our constitutional republic was well designed to slow what Edmund Randolph called the “fury of democracy.” It was not intended to provide politicians with opportunities to avoid taking action.

James Madison, who drafted the Constitution, said the six-year term of senators was intended to ensure that the Senate proceeded "with more coolness, with more system, and with more wisdom, than the popular branch [the House of Representatives]." While the news cycle changes daily, the issues addressed by our Congress should not.