David E Hoffman Russias parliament has approved the New START treaty. The Senate has ratified it. You might think that its time to stop worrying about the bomb, arms control and all that mind-numbing stuff from the Cold War. You know: Mutual Assured Destruction, Dr Strangelove, the Evil Empire. Its all been tossed into the trash bin of history, right? Not entirely. While the new treaty is a small step in the right direction, there will still be as many nuclear warheads in the United States and Russia uncovered by this treaty as those which are covered. The treaty limits each side to a total of 1,550 strategic nuclear warheads, for a total of 3,100. But it does not cover several thousand Russian tactical nuclear warheads, about 500 US tactical nuclear weapons, nor the US strategic reserve, about 2,000 warheads, not deployed, which are being kept on hand, just in case. So before everyone in the stadium gives the new treaty a big cheer, keep an eye on whats lurking in the parking lot. Thats the next problem for arms control: make sure there are no weapons out of bounds, beyond the playing field, where they can escape verification. Meanwhile, intercontinental ballistic missiles are still on launch-ready alert, another legacy from the Cold War we havent yet dealt with. Is there any reason for both sides to maintain the threat to launch fastin our case, four minutes for land-based missiles from the time an order is givenif we are no longer adversaries? Do we not have the willpower to de-alert, or negotiate a delay in the possible launch of missiles on both sides? So, in the sense that we need to bring it up to date, nuclear deterrence is still with us. The missiles and warheads and bombs are still out there. The software changed when the Cold War ended, but the hardware lingers. The horrible suicide bombing at Moscows Domodedovo airport this week serves to underscore another point. Nuclear deterrence meant posing a threat to retaliate that was so credible that your adversary would not attack. The launch-ready alert status was good for that: a powerful, credible threat. Nuclear deterrence was hugely expensive, filled with all kinds of dangers, but it seems to have worked, or at least not failed, in the Cold War years. A nuclear bomb was not used in combat after World War II. (A couple thousand of them were tested, however, in real explosions that left scars on the Earth.) Then it all ended. Today, there is no single adversary in the world that threatens the United States like the Soviet Union did. And nuclear deterrence is greatly diminished against many contemporary threats. Terrorists carrying a suitcase full of explosives and shrapnel into an unguarded airport arrivals hall are not deterred by nuclear missiles. Nor are cyber warriors. In fact, deterrence depended on a rational adversary who could be identified. Todays threats are more diffuse, harder to pinpoint and dont seem to be wowed by nuclear warheads of any kind. This reality confronts all the nuclear powers. So, we have to finish cleaning up the legacy of the Cold War, but at the same time, discover entirely new methods to cope with new dangers. Nuclear deterrence isnt dead, but it wont unlock all the doors to our future, either. Foreign Policy