Eric Edelman was undersecretary of defense for policy from 2005 to 2009. Robert Joseph was undersecretary of state for arms control and international security from 2005 to 2007.

President Obama has announced the next step in his quixotic quest to achieve a nuclear-free world. Speaking at the Brandenburg Gate this week, the president proposed reductions in U.S. nuclear forces to about 1,000 deployed strategic warheads; that represents a cut of more than 30 percent from the level of the 2010 New START agreement. While the offer was placed in the context of a bilateral agreement with Russia, Obama’s words were carefully chosen. He did not rule out unilateral reductions — something the president’s top advisers have indicated might happen if Moscow refuses to reduce its forces — or pursuing an arrangement outside of the constitutional treaty process.

The president emphasized that the new warhead level is derived from a recent Defense Department study. According to administration officials, the study, which remains classified, sought to identify requirements for our nuclear forces and opportunities for reductions. Before the analysis began, some predicted that the president’s commitment to “global zero” would lead to a deployed force of 1,000 warheads based on “political guidance” to military authorities that arbitrarily reduced the scope of assets required to ensure deterrence.

The view that the numbers would be cooked to support a disarmament agenda is reinforced by the testimony of military leaders during and after the ratification of New START. Gen. Kevin Chilton, then the head of U.S. Strategic Command, told the House Armed Services Committee that the 1,550 warheads permitted by New START was as low as he would recommend going under existing global security conditions. What has changed in the past three years to allow for further reductions?

In recent months, North Korea has launched a long-range ballistic missile and conducted a third nuclear test. Iran is closer to achieving nuclear weapons capability. India and Pakistan have increased their nuclear arsenals. China, according to the Pentagon, is developing a road-mobile intercontinental ballistic missile — perhaps with MIRV (multiple independently targeted reentry vehicle) warheads — and is constructing two additional strategic submarines to be outfitted with advanced nuclear missiles. And Russia is expanding its nuclear forces on land, at sea and in the air. Moscow has announced that a new ICBM will enter service this year, that it has begun research and development for a rail-mobile missile, and that it will commission two strategic submarines this year and resume continuous patrols. In February, Russian Bear-H bombers circled Guam, the fastest-growing U.S. base in the Pacific.

The prospects for concluding an arms control treaty with Russia are dim. Moscow has made clear that any agreement must be accompanied by limits on U.S. missile defenses and conventional long-range-strike weapons — conditions rejected in the Senate resolution ratifying New START. Moscow has also objected to including non-strategic nuclear weapons in any negotiations. Addressing the vast disparity in these forces was a point of consensus in the ratification debate, with the Senate calling on the president to pursue an agreement “to secure and reduce tactical nuclear weapons in a verifiable manner.” Separately, in its recent markup of the Defense Authorization Act, the House Armed Services Committee drew attention to Russian violations of existing arms control agreements as a barrier to further reductions.

For these and other reasons, the president is likely to forgo the treaty route in pursuit of an agreement with Russia. Doing so would be inconsistent with the conditions the Senate set for its consent to New START. Yet the president seems determined to go to lower numbers, either by circumventing the formal treaty process with an executive agreement or, if that fails because of Russian objections, by unilateral reductions.

The Obama administration’s intention to “lead by example” reflects its deep ideological commitment to disarmament. No other country is following the U.S. lead. None has followed in adopting a policy of developing no “new nuclear warheads.” None has followed in allowing its nuclear weapons infrastructure to rust out from within as a consequence of budget cuts and policy neglect. And none will be persuaded by the latest presidential endorsement of “nuclear zero.”

More cuts will only increase the risk to U.S. security and that of our allies. Going to 1,000 deployed warheads will further weaken the perception of U.S. capability and resolve held by adversaries and friends alike. It could encourage China to increase its nuclear forces to match those of the United States, as the Russians noted in their initial reaction to the speech. And it would certainly undermine the credibility of U.S. security commitments, contributing to further proliferation and a more dangerous world.

Fifty years ago, President John F. Kennedy gave a forward-looking but realistic speech in Berlin that offered a more constructive relationship with the Soviet Union. His remarks recognized the United States’ central role in global politics and the essential need for U.S. power. He specifically acknowledged the requirement to fully fund the nuclear arsenal. Kennedy committed the United States to maintaining, in his words, a nuclear capability “second to none.” This policy has been followed by every president until today.