Russia feared the destabilizing effects of U.S. missile defenses on the current nuclear balance. For this reason, Russia wanted to retain the 1972 Anti-Ballistic Missile (ABM) Treaty, which limited each side to defending one site with only 100 interceptor missiles. The ABM Treaty also prohibited the development of systems that could defend all of Russia or all of the United States. Russia worried that even though a U.S. national missile defense might begin on a small scale, it could grow more robust over the years. Expanded U.S. defenses would require Russia to build more offensive missiles to overcome them and retain a credible nuclear deterrent, triggering a nuclear arms race. Russia may also have been concerned that a U.S. BMD system might prompt China to expand its own strategic nuclear force, making China more of a threat to Russia.

In the 1970s, the United States and Russia each deployed anti-ballistic-missile defenses at a single location in each country. The defensive missiles were tipped with nuclear weapons. The 1972 ABM Treaty limited these deployments. The United States closed down its ABM system in 1978, three years after it was deployed. Russia's ABM system, on the outskirts of Moscow, is still operational.

President Bush, however, argued that the ABM Treaty should be modified or dissolved to allow the United States to develop small-scale defenses that could protect all of the United States from a limited number of missiles launched from countries like North Korea or Iran. The President claimed that such missiles pose a new threat to the United States and its allies. Bush also said that the ABM Treaty was a "relic" of the past and was no longer needed because the United States and Russia were no longer enemies.

Rather than simply withdraw from the ABM Treaty, however, President Bush stated in mid-2001 that he wanted to develop a new "framework" with Russia. In this framework, the ABM Treaty would be modified or scrapped by mutual agreement and both sides would agree to significant reductions in their existing nuclear arsenals.

In his budget for the U.S. Department of Defense for Fiscal Year 2002, President Bush declared his intention to eliminate long-range (strategic) missiles carrying a total of 1,000 nuclear warheads.

Russia, however, rejected the U.S. proposals to end the ABM Treaty by mutual agreement. This led the United States on December 13, 2001, to announce its intention to withdraw from the ABM Treaty in six months (as permitted under Article XV of the treaty) in order to pursue the testing of missile defense systems and components that would have been banned by the agreement. Russia, who said that its nuclear arsenal would be sufficiently large to overwhelm the missile defenses that the U.S. intends to deploy in the next decade, if not longer, reacted in a restrained manner to this announcement, and it appeared that this step by the United States would not seriously injure U.S.-Russian relations or the prospects for significant nuclear weapon reductions by the two countries. On December 17, 2001, two weeks after the U.S. announcement of its intended withdrawal from the ABM Treaty, Russian President Vladimir Putin announced that Russia would accept the proposal by President George W. Bush to reduce over the next ten years the number of warheads each country deploys on strategic delivery systems to between 1700 and 2200.  The U.S. officially withdrew from the ABM Treaty on June 13, 2002.

If the United States deploys missile defenses Russia might decide to keep its multi-warhead (MIRVed) ICBMs which would have been eliminated under START II—a treaty that for Russia was linked to the continued existence of the ABM Treaty and was terminated by Russia after the U.S. withdrew from the ABM Treaty in June 2002. Of all the mentioned Russian countermeasures to BMD, placing multiple warheads on its ICBMs would probably be the cheapest and easiest to implement since it would allow Russia to saturate missile defenses.

Small-scale U.S. missile defenses would have little if any impact on Russia's ability to inflict unacceptable damage on the United States in response to a strike. From the Russian point of view, the traditional logic of deterrence remains intact, limiting the concern about U.S. withdrawal from the ABM Treaty. The key is providing confidence to Russia that any new U.S. missile defenses will remain limited.

Reassuring Russia may be difficult, however. With limited economic resources available, Russia is constrained in its choices regarding its nuclear posture and does not now plan to maintain a large nuclear arsenal. At the same time, the current cooperative relationship between Russia and the United States does not merit large spending on its nuclear forces. However, even if U.S. ballistic missile defenses begin on a small-scale, future expansion of BMD may cause Russia to reconsider its nuclear policy. For this reason, Russia's concerns about U.S. missile defenses will not be easy to address.