Reports this week that government testers got into the country with false IDs are sure to turn up the volume on calls for a “more secure” national identification system. But identity-based security cannot — and should not — be fixed.

Why are we asked for identification cards in the first place? The theory is that there is greater security when someone can examine your background or track your movements.

It’s true that surveillance makes law-abiding people easier for authorities to control. People required to show ID could, for instance, be run against databases of outstanding fines and tax delinquencies at local shopping malls. But identification gives the government no similar control over terrorists and sophisticated criminals — the people we’re trying to stop with these ID checks.

To do identity-based security, you need to know who people are in the first place. That’s not easy to do with lawbreakers.

To start, the U.S. has a substantial trade in false documents good enough to fool Department of Motor Vehicle employees. And criminals regularly corrupt DMV workers to procure false drivers’ licenses. Can this problem be curtailed? Yes. Solved? No. Even if we had the strongest possible national ID card — a cradle-to-grave, government-mandated, biometric tracking system — the greatest weakness would still remain: Knowing who a person is does not reveal what they plan to do.

Examples are legion in terrorism, and routine in crime, of people with no history of wrongdoing being the ones who act. For the 9/11 attacks, Al Qaeda selected operatives without records of involvement in terrorism.

In the end, talk about creating a foolproof ID card distracts us from making honest improvements in security that address tools and methods of attack directly. Strong cockpit doors and self-reliant passengers prevent commandeering of airplanes no matter who is onboard. That is real security.

What’s more, the negative consequences of a national ID card would be profound. Lawful trade and travel would be disrupted for ID checks, at a substantial cost to both liberty and commerce. What little benefits we’d reap would not be worth such a high price.

It’s possible to “fix” the identification problem, but it doesn’t solve the security problem. A national ID system would provide a tiny margin of security — and almost none against threats like terrorism.