Yesterday’s blog post described the coming budget challenges for the U.S. strategic triad, important elements of which are slated for modernization beginning in the next decade. Updating the legs of the triad could impose steep costs on the Defense Department budget in the 2020s and thereafter. It is difficult to see how the triad will be able to escape the consequences of tightening defense budgets. Further arms control steps could help.

Some analysts question the need to continue to maintain a triad, asserting that elimination of one leg could generate substantial savings. Looking at the pending modernization needs, elimination of submarine-launched ballistic missiles (SLBMs) and ballistic missile submarines (SSBNs) could generate the greatest cost savings. But the sea-based leg of the triad has long been seen as the most survivable and most important, as evidenced by the fact that, under the New START Treaty, SSBNs will carry well over 60 percent of permitted U.S. deployed strategic warheads.

Many who favor moving from a triad to a dyad argue for eliminating the ICBM (intercontinental ballistic missile) leg. They note that ICBMs in fixed silos are vulnerable to attack. True, perhaps, but the Air Force decision to deploy only one warhead atop each Minuteman III makes them a much less attractive target than when the Minuteman III carried three warheads. An adversary would now have to target one or even two warheads on each Minuteman silo in order to destroy a single warhead — hardly an appealing exchange ratio.

Another reason argues for keeping ICBMs. An adversary wishing to destroy U.S. ICBMs in their silos would have to pour hundreds of nuclear warheads into the American heartland. A nuclear response would be assured — and would thus deter the attack in the first place. And, if the Air Force can come up with a life extension plan for the Minuteman, ICBMs could be relatively inexpensive to update.

This is, in any case, something of an academic debate. Current U.S. policy is to maintain a triad, and the concept enjoys broad popularity in the Pentagon and on Capitol Hill. The result of any budget reductions for the future triad — or of an arms control agreement that reduces U.S. (and Russian) strategic forces below the levels of New START — will most likely be reductions in two or three legs of the triad rather than abandonment of one.

Significant savings can still be found. If, for example, the new SSBN program were reduced from 12 boats to 10, the Navy would save $6-7 billion in construction costs and close to $20 billion in operating costs per boat — for a total savings of some $50 billion. Granted, these savings would be realized over many years (and later rather than sooner), but that can be said about reductions for virtually any large Pentagon weapons program. It makes sense to think about out-year budget savings as the kinds of pressure that we see on defense spending today will be with us for years, if not decades, to come.

There is, moreover, plenty of room to reduce U.S. strategic forces below the levels of New START and still maintain a strong triad.

In June in Berlin, President Obama proposed a one-third reduction in New START’s limit of 1550 deployed strategic warheads. That would reduce the limit on U.S. and Russian deployed strategic warheads to 1000-1100. Administration officials privately indicate that there would be a commensurate reduction in the limit of 700 deployed strategic missiles and bombers. That could bring that limit down to 500.

The U.S. military could comfortably maintain a strategic triad within the limits of 500 deployed strategic missiles and bombers, and 1000-1100 deployed strategic warheads. Using current New START counting rules, such a triad might look like the following:

  • 300 deployed ICBMs, each carrying a single warhead = 300 deployed warheads
  • 40 deployed bombers, each counted as a single warhead = 40 deployed warheads
  • 160 deployed SLBMs carrying multiple warheads deployed on ten ballistic missile submarines = 660-760 deployed warheads (depending on whether the overall deployed warhead limit was 1000 or 1100)

This would be a robust and survivable strategic force, capable of deterring any adversary contemplating major aggression against the United States and its allies.

Some analysts would argue that 1000-1100 deployed strategic warheads — particularly as the Joint Chiefs of Staff have validated that number as sufficient to provide for an effective deterrent — could be implemented unilaterally, without regard to what other countries might deploy. That logic traces back to the George W. Bush administration, whose 2001 nuclear posture review determined that the United States needed 1700-2200 operationally deployed strategic warheads. Bush administration officials said the U.S. military would deploy that number … regardless of what Russia or China might deploy.

It would be preferable, however, to implement further strategic reductions below New START’s limits in conjunction with parallel reductions by Russia, whose force size is a primary driver of U.S. strategic force levels. Further U.S.-Russia arms control thus appears to be very much in the U.S. interest: if budget pressures are likely to drive down future U.S. strategic force levels — as they appear to be — it makes sense to seek negotiated limits that would bring down Russian strategic force levels in parallel.

True, Moscow has shown little interest of late in further reductions below the limits of the New START Treaty. But that position could change. Just as the United States faces future large expenditures to maintain its strategic triad, the Russians face similar large expenditures, and they face them now. Russian strategic force numbers are already well below New START’s limits on deployed strategic warheads and deployed strategic missiles and bombers. Rather than building back up to 1550 and 700 — and the most optimistic projection does not show Russia getting back to the latter limit until the late 2020s, if ever — negotiated reductions would reduce the cost burdens on both countries.

Additional nuclear reductions may become of greater interest to the Kremlin if the Russian economy continues to stagnate. And if the prices for oil and gas decline, that could have a major negative impact on the Russian federal budget.

There are a variety of reasons why nuclear arms reductions beyond New START make sense for the United States: to reduce the number of nuclear weapons that could threaten America, to expand the negotiating mandate to address non-strategic nuclear arms, to increase transparency, and to enhance the credibility of U.S. diplomacy to block nuclear proliferation. If defense budgets are going to drive the United States invariably to lower strategic force numbers, locking in arrangements that ensure that America’s nuclear peer also reduces offers one more compelling argument for nuclear arms control.