*legislate seat belt laws*

*car crash deaths go down*

"See? We didn& #39;t need those seat belt laws."

Two qualifiers:

1. Seat belt laws might not be the only thing that decreased them but you can& #39;t assume it would have happened anyway.

2. Taking precautions inherently means the thing you& #39;re preparing for might not happen. Doesn& #39;t make the precaution unnecessary in hindsight.

"I wore a seat belt but didn& #39;t get into a car crash. Might as well not have worn it" is an argument often made against gun ownership. Nearly 100% of gun owners never discharge it in self-defense. Does that mean they shouldn& #39;t have one *just in case*?