In his State of the Union address on Tuesday, President Barack Obama will reportedly reiterate his interest in reducing the threat of nuclear weapons, though unlikely to announce specifics. The administration is interested in seeking an agreement with Russia, building on the New Strategic Arms Reduction Treaty (START) of 2010 and cutting U.S. strategic nuclear forces by another third in the expectation that Moscow will do the same with its nuclear arsenal.

This would leave each country with roughly 1,000 deployed long-range warheads, plus several thousand more in reserve and in tactical arsenals.

It would be an appropriately modest step toward serious pursuit of Obama’s (and President Ronald Reagan’s) goal of a nuclear-free world. With 1,000 warheads, the U.S. nuclear arsenal would remain more than capable of targeting any reasonable set of military sites abroad. Washington and Moscow would also avoid tempting any medium-size nuclear powers, most notably China, with its 250 or so warheads, to pursue nuclear superpower ranks.

It is sound policy.  Dramatic enough to make a major difference in Obama’s foreign policy legacy yet measured enough to sustain U.S. deterrence for Washington and its allies abroad. Still, it will work best if several additional steps are included:

  • Modest U.S. unilateral cuts are a reasonable way to jump-start the process if Moscow is not immediately amenable to reciprocative measures. But they should be modest and reversible ‑ until we see how Russia reacts. This is not about fear of a U.S.-Russian nuclear exchange, but rather about avoiding the possibility that Moscow would become more assertive if it somehow felt empowered by a new position atop the nuclear hierarchy.
  • Tactical and surplus warheads should be constrained. As a first step, data exchanges and some informal monitoring provisions should be explored. U.S.-Russian arms-control treaties have not previously limited warheads in these inventories. Since they are not normally affixed to big missiles or bombers, they are harder to track. But that is why they must be limited in some way. We will need to improve monitoring methods for these warheads if other countries are to be brought into the nuclear arms-control process in future rounds, since most other nations’ arsenals are dominated by these shorter-range weapons.
  • Missile defenses need to be part of the process. Since the United States withdrew from the Anti-Ballistic Missile Treaty during the George W. Bush administration, there have been no ceilings on any type of missile defenses. There is little point here in trying to put Humpty Dumpty back together. Not only do congressional Republicans strongly oppose any limits on U.S. missile defenses but the technologies are evolving too fast (and are still too immature) for restraints to make much sense. Especially since some missile defense capability is a reasonable desire for those worried about North Korean and Iranian threats. But greater transparency, some degree of actual collaboration between the United States and Russia and, depending on the evolution of not just the technology but also the threat, some greater flexibility regarding U.S. plans to put advanced missile defenses into Europe in the future makes sense. The flexibility should not go so far as to weaken Washi! ngton’s bonds with allies and should not prevent the United States and its allies from protecting themselves. This point needs to be made plainly to Moscow. 
  • Third parties should be asked to promise restraint, too. The other U.N. Security Council Permanent Five nuclear powers  ‑ Britain, France and China  ‑ as well as Israel, India and Pakistan should promise not to exceed current arsenal sizes, or at least not by much. This need not be a deal breaker if they refuse. But it would be a useful complement that would help ensure that no new nuclear competition is triggered by U.S. and Russian cutbacks, and would help pave the way for future multilateral treaties. To help persuade the other nuclear powers to agree, all countries could be asked to promise not to develop or augment existing nuclear weapons inventories. In other words, language could be proposed that would allow non-nuclear states to make the same pledge, and that would not require countries such as Israel to acknowledge officially that they have nuclear weapons. (Since right now they might not.) 
  • Other arms-control measures could be considered. Top of the list is ratification of the 1990s-era Comprehensive Test Ban Treaty, which the United States and China, among the world’s declared nuclear powers, have not yet ratified. (The Senate voted it down in 1999.) Another ratification debate is not prudent if it leads to a formal Senate defeat. But this is an opportune moment to remind Americans that our current arsenal is holding up extremely well without testing, and to make the case for formalizing our testing restraint. The last U.S. test was in 1992; no state other than North Korea has tested in the last dozen years.

Obama has rightly seized this nuclear arms-control opportunity. It may or may not make him the president who started the real march toward a nuclear-free planet. Indeed, that may not even be a realistic or desirable goal at this stage.

But his plan should help future presidents and Congresses evaluate the wisdom of such a possible step. Meanwhile, it saves a little money and, more important, helps keeps America and her allies safe.