No, the United States isn't immune to nuclear attack. But you can bet it's not going to come courtesy of the Taepodong-2 missile the North Koreans fired recently.

North Korea has yet to demonstrate that it has a long-range missile that can shoot straight. The Taepodong-2 barely got off the pad -- and that's eight years after the last test, which also failed.

And if the North Koreans somehow make the Taepodong-2 work, they still have a problem. When you fire an intercontinental ballistic missile, it gets people's attention. The North Koreans can't be sure the handful of warheads they might be able to launch would penetrate even the limited missile shield we already have. Plus, we'd know where they were fired from. We'd fire back, and there wouldn't be much of North Korea left after that.

So despite the warning we're hearing from some critics -- that North Korea poses a bigger threat today than it did eight years ago -- the fact is, we have the military capability to keep this threat contained. Besides, master strategist Kim Jong Il has managed to annoy all his regional neighbors, helping U.S. officials secure North Korea's political isolation as well.

We also shouldn't spend much time fretting over the other over-hyped nuclear threat -- that Kim will slip a nuclear weapon into the United States inside an ordinary shipping container. The nuke-in-a-box scenario is an unlikely terrorist tactic. No intelligent enemy would take the world's deadliest weapon, crate it up and wave goodbye. Too much could go wrong on a long, unsupervised sea voyage, jeopardizing the reliability and security of the warhead.

If a country was serious about wanting to attack the United States with nuclear fire in a manner that would ensure surprise, leave no fingerprints and guarantee success, there's a much easier, better and cheaper way. It's one that could avoid the challenge of smuggling weapons into U.S. ports under the eyes of law enforcement, intelligence, customs officials and the Coast Guard: Put the missile on a ship disguised as a commercial freighter or private craft, sail near American waters and fire.

The North Koreans could adapt a short-range missile, such as a Scud. They already have them, and they know they work. The Scud has a large "throw-weight" (meaning it can carry a very heavy warhead) and could deliver a weapon at close range with ease. Building an improvised vertical launch platform for the missile is no significant technical challenge, nor is figuring how to make firing accurate enough to shoot a nuke at New York or Washington.

What's better (from an enemy's standpoint) is that the missile firing might well go undetected. Even tracing the perpetrator after the fact might be tough, particularly if the ship were scuttled after the firing. We wouldn't know who to retaliate against.

Now that's a real threat -- one we should take seriously.

The United States could develop the means to counter this danger. One of President Bush's most important initiatives was the Proliferation Security Initiative, a cooperative partnership of nations that work together to track the smuggling of nuclear weapons and technologies. In December 2002, a Spanish warship temporarily halted a North Korean freighter with a concealed shipment of Scud missiles bound for Yemen; that was part of PSI. The United States also is developing short-range sea- and land-based missile defenses. These could be used to defend against a covert missile threat.

No, North Korea's fireworks shouldn't cause us to overreact. But we shouldn't be complacent, either. Kim's nuclear weapon and missile programs are a danger to the peace and security of the region and the United States. What's required is a judicious mix of offensive deterrence, defensive missile shields, vigilant counter-proliferation programs and tough diplomacy.

Only then can we keep a dangerous regime from becoming a deadly one.

James Carafano is senior fellow at The Heritage Foundation and co-author of "Winning the Long War: Lessons from the Cold War for Defeating Terrorism and Preserving Freedom."