Barry Blechman’s criticism [“A slimmer, smarter nuclear force,” op-ed, July 6] of Eric Edelman and Robert Joseph [“Obama is pursuing nuclear folly,” op-ed, June 23] was off-target.

Mr. Blechman called for the United States to “move unilaterally” to lower nuclear force levels, which he argued “would save a lot of money . . . without jeopardizing U.S. national security or that of our allies.”

Such thinking is common among those who favor the elimination of nuclear weapons, but it is also dubious. The savings from reducing the number of deployed nuclear weapons from 1,550 to about 1,000 are negligible compared to the costs of building up conventional land, sea and air forces, which Mr. Blechman appeared to favor. Moreover, further reductions in the U.S. nuclear arsenal could induce China to seek nuclear parity with the United States and cause allies who rely for their own security on the U.S. extended deterrent to doubt its continued viability and to acquire their own nuclear arsenals.

Despite the Obama administration’s “reset” with Russia and desire to reduce nuclear stockpiles, Russia is placing increasing primacy on nuclear weapons. In recent years, Russia has allocated substantial resources to modernizing every element of its own strategic “triad” of nuclear forces. Evidence suggests Russia is violating its nuclear arms treaty commitments. Yet people continue to call for unilateral U.S. nuclear weapons reductions.

Deterrence remains an art, not a science. We cannot know with certainty what level of nuclear forces will reliably deter adversaries and assure allies. But given recent developments in Russia, North Korea, Iran and elsewhere, calls for more U.S. nuclear weapons cuts appear out of touch with reality.

David J. Trachtenberg, Burke

The writer, president and CEO of Shortwaver Consulting, was a senior Pentagon policy official in the George W. Bush administration.