When a terrorist massacred 50 people at two New Zealand mosques last week, Prime Minister Jacinda Ardern immediately grasped the nettle. “I can tell you one thing right now,” she told a news conference. “Our gun laws will change.”

That’s what effective leadership looks like. New Zealand’s cabinet has now agreed in principle to overhaul those laws, experts are reviewing ways to make the country safer from firearms and, Ardern promised, “within 10 days of this horrific act of terrorism, we will have announced reforms.”

Contrast that with the United States, where just since 1970, more Americans have died from guns (1.45 million, including murders, suicides and accidents) than died in all the wars in American history (1.4 million). More Americans die from guns every 10 weeks than died in the entire Afghanistan and Iraq wars combined, yet we still don’t have gun safety rules as rigorous as New Zealand’s even before the mosques were attacked.

The N.R.A. (not to be confused with the vast majority of gun owners) will turn to its old smoke-and-mirrors standby, arguing that the killer’s hate, not his guns and bullets, were the real problem.