US lawmakers are very reactionary in the case of gun laws too, it's just that gun owners usually have enough political pull to block them from successfully getting laws passed. (The current campaign for gun control is 100% a reactionary response to whatever's been making the biggest news headlines. For example, the vast majority of US gun homicides are carried out with handguns, yet gun control supporters seem to think it's absurd they're more tightly regulated than AR-15s - which are relatively rarely used to kill anyone and have more mundane uses for things like hunting - just because the AR-15s are in the headlines. The US's most deadly school shooting was done with handguns too.) In fact, I'd argue the reactionary nature of US lawmaking is important to understanding why "sensible", "common-sense" gun control laws are so strongly opposed in the first place.