Still, by placing defensive missiles that Moscow opposes on Polish soil, NATO and Poland are sending a message that we’re serious about the Iranian threat, and that we’re willing to stand against Russia when it overreaches.

That’s exactly what our old Cold War foe did last month by invading democratic Georgia and claiming to have annexed regions of it. And it’s no coincidence that, almost immediately after that invasion, the Polish government officially agreed to allow the missile bases. There’s no reason for anyone to expect Russian bellicosity to stop at the Georgian frontier, and the Poles are smart to want more secure ties with NATO and the U.S.

The U.S. needs to act, too.

Lawmakers here should show their support for expanding missile defense by passing a “sense of the Congress” statement that endorses the rapid deployment of missile defenses in Europe. They also should restore the cuts made to the Bush administration’s annual appropriation request for missile-defense programs.

Yes, we live in a dangerous world. But a strong missile defense can make that world safer, by reminding untrustworthy regimes that unprovoked aggression won’t stand.