Authorities respond to the scene of the shooting last week at the Grand Theatre in Lafayette, La. (Leslie Westbrook/Associated Press)

Since 9/11, the United States has responded aggressively to the danger of terrorism, taking extraordinary measures, invading two countries, launching military operations in many others, and spending more than $800 billion on homeland security. Americans have accepted an unprecedented expansion of government powers and invasions of their privacy to prevent such attacks. Since 9/11, 74 people have been killed in the United States by terrorists, according to the think tank New America. In that same period, more than 150,000 Americans have been killed in gun homicides, and we have done . . . nothing.

Our attitude seems to be one of fatalism. Another day, another mass shooting. Which is almost literally true. The Web site documents that in the first 207 days of 2015, the nation had 207 mass shootings. After one of these takes place now, everyone goes through a ritual of shock and horror, and then moves on, aware that nothing will change, accepting that this is just one of those quirks of American life. But it is 150,000 deaths. Almost three Vietnams.

After last week’s incident in Lafayette, La., the governor of the state and Republican presidential candidate, Bobby Jindal, pointed his finger at what has now become the standard explanation for these events: “Look, every time this happens, it seems like the person has a history of mental illness.”

But it makes little sense to focus on mental health. The United States has a gun homicide rate that is at least a dozen times higher than those of most other industrialized countries. It is 50 times higher than Germany’s, for instance. We don’t have 50 times as many mentally disturbed people as Germany does — but we do have many, many more guns.

At least we have stopped blaming gun violence on video games. Perhaps someone noticed that other countries have lots of violence in their pop culture but don’t have this tsunami of gun deaths. Japan, for example, is consumed by macabre video games and other forms of gory entertainment. In 2008, Japan had just 11 gun homicides. Eleven. Why? Hint: It has very tough gun-control laws.

Jindal at least suggested that states follow or even strengthen laws to make sure that mentally unstable people can’t buy guns, but this has placed him beyond the pale for the gun lobby. Former Texas governor Rick Perry’s solution is to loosen the few restrictions on guns that do exist so that, in the Lafayette movie theater, other patrons could have been armed and would have shot the gunman.

The notion that the solution — in dark, crowded movie theaters — is a mass shoot-out is so dangerous that it should rule out Perry as a serious Republican presidential candidate. When asked about such proposals after the mass shooting in a movie theater in Aurora, Colo., William Bratton, who has now been police chief in three major U.S. cities, dismissed the idea. To him the solution is obvious. “[We need] some sanity in our gun control laws. . . . Gun control can reduce these numbers of incidents,” he told CNN.

We have become so inured to the catastrophic levels of violence in our cities that we gloss over them. People often ask me if I think it’s safe for them to travel to countries such as Egypt or Morocco. The reality is that many major U.S. cities have homicide rates that are many times higher than those in places such as Cairo or Casablanca. (And it’s worth noting that non-Islamic terrorists — as in Charleston, S.C. — have killed almost twice as many people as jihadis have in the United States since 9/11.)

In the wake of this ongoing tragedy, we have actually loosened restraints on the ability and ease with which people can buy, own and carry guns. This is partly because in June 2008, the Supreme Court broke with 200 years of precedent and — in a 5-to-4 decision written by Justice Antonin Scalia — created an individual right to gun ownership that has made common-sense regulation of guns much harder.

In his powerful dissent in that case (District of Columbia v. Heller), Justice John Paul Stevens pointed out that Scalia’s opinion was an act of extreme judicial activism — that for two centuries, federal courts had recognized that the government had the power to regulate the sale of firearms, and that the Supreme Court in particular had for at least seven decades consistently affirmed that interpretation.

It is not an act of fate that has caused 150,000 Americans to die over the past 14 years. It is a product of laws, court decisions, lobbying and pandering politicians. We can change it.

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