I was unimpressed with the security arguments made by the chairman and ranking member of the House Homeland Security Committee in a letter to appropriators the other week. Citing the “commando-style” terrorist raid on a train station in Mumbai last year, the letter objected to language in the Transportation, Housing and Urban Development, and Related Agencies Appropriations Act that would require Amtrak to allow firearms in checked luggage.

But the risk of a commando-style raid does not support—in fact it undermines—the authors’ argument that weapons should be banned on passenger trains. With law-abiding citizens fully disarmed, any terrorist raiders would know that they are more free to cut a deadly swath through an innocent population.

It was counterattack by civilians that prevented a fourth plane from being used as a guided bomb on September 11, 2001. Disarming the law-abiding citizen is contrary to the lesson of that day.