FactChecking Biden’s Claim that Assault Weapons Ban Worked

President Joe Biden claims the 10-year assault weapons ban that he helped shepherd through the Senate as part of the 1994 crime bill “brought down these mass killings.” But the raw numbers, when adjusted for population and other factors, aren’t so clear on that.

There is, however, growing evidence that bans on large-capacity magazines, in particular, might reduce the number of those killed and injured in mass public shootings.

A day after the Boulder, Colorado, mass shooting, in which 10 people were killed by a gunman in a grocery store...