Or should I lobby for increased gun control?

For months after the Columbine massacre, people were constantly telling one another: “I wish I’d been there, I would’ve tackled that guy.” My Chatfield classmates and I would stand on the steps of our school and watch as Columbine survivors limped into class on their crutches. The reality, of course, is that we wouldn’t have tackled the shooters. Shooters aren’t tackled until their clips are empty, and by then it’s too late.

Serving in a combat zone means constant vigilance against unseen enemies. It means wearing heavy body armor, no matter what the weather is doing. It means taking weapons with you when you eat or use the restroom. It means, quite literally, never putting them down. The common argument made by gun-rights advocates is that they “don’t want to be in a one-way firefight,” which argues for not restricting the sale of things like semiautomatic weapons, high-capacity magazines and tear-gas grenades. Their contention is that the only real way to stop dedicated shooters is for there to be plenty of other shooters around.

Those who truly believe that need to be carrying a gun right now, wherever they are. They need to keep it closer than I kept my weapon in Iraq. In Iraq my fellow soldiers’ lives were on the line. Soldiers’ lives are important — but our families’ safety is even more precious.

Those who truly believe that anyone should be able to buy semiautomatic weapons will need a gun at soccer practice, at church, at “Batman” movies. That’s the only logical choice. And civilian life will feel almost like being in Iraq.

The Brady Campaign to Prevent Gun Violence has compiled a 62-page list of mass shootings since 2005. What’s striking is that there isn’t a single example of a concerned bystander with a concealed-carry permit who stopped a mass shooting. I believe that what I learned in Iraq holds true for the United States: constantly carrying weapons is harder than it sounds, and a determined gunman will orchestrate a mass shooting precisely where and when we are least prepared for it.