Not since Jimmy Carter and Ronald Reagan, decades ago, talked of abolishing nuclear weapons has an American president pledged to work toward that goal. Yet, speaking in Prague on April 5, 2009, President Barack Obama proclaimed "clearly and with conviction America's commitment to seek the peace and security of a world without nuclear weapons."

Furthermore, Obama linked his announcement of this lofty aim with a discussion of specific actions that his administration would take in 2009. These included signing a new Strategic Arms Reduction Treaty (START) with the Russians-one setting the stage for further nuclear cutbacks involving all nuclear weapons states-pursuing U.S. Senate ratification of the Comprehensive Test Ban Treaty (CTBT), and negotiating an agreement with Iran to avert that nation's development of nuclear weapons.

This ambitious nuclear disarmament agenda has a number of things bolstering it. A START Treaty seems particularly negotiable. At peace with one another and with upwards of 95 percent of the world's 26,000 nuclear weapons in their possession, Russia and the United States have little need for vast, unnecessary Cold War-style nuclear arsenals. Moscow proposed sharp reductions years ago and, with even Senate Republicans in favor of U.S.-Russian arms agreements, Washington now seems ready to accept a new START treaty that would slash U.S. and Russian nuclear arsenals to no more than 1,500 nuclear weapons each.

Ratification of a nuclear test ban treaty also has considerable momentum. Negotiated and signed by President Bill Clinton in 1996, the CTBT enjoys substantial popularity among the American people and has already been ratified by such U.S. allies as Britain, France, and Germany, as well as by numerous other nations, including Russia. Furthermore, as there has been no U.S. nuclear testing since 1992, the U.S. government would gain (rather than lose) by setting up verification procedures to see to it that other nations, as well, refrained from nuclear tests and, thus, could not develop nuclear weapons.

Although a non-proliferation agreement with Iran seems less promising, it too remains feasible. By opening direct negotiations with Iran, the Obama administration has eased the sharp U.S.-Iranian confrontation of recent years. In addition, by making plans to eliminate much of its own nuclear arsenal, the U.S. government has undercut the sense of grievance that Iran and other Third World nations feel at a U.S. double standard when it comes to nuclear weapons. Moreover, it is not at all clear that the Iranian government is developing nuclear weapons or, if it is, that it is unwilling to stop some steps short of their actual production-a situation that might prove an acceptable compromise to both Iran and other nations.

But what about the broad goal of a nuclear-free world? Here, too, there is some cause for optimism. Even during the election campaign, Obama spoke and wrote of nuclear abolition, and there is no reason to assume that he has changed his mind on that score. Furthermore, the idea of nuclear abolition-long popular with the general public-has been gaining support in recent years from political elites, particularly former national security officials. Even many high-ranking military officers have begun to wonder about the value of these weapons that they are never able to use.

Nevertheless, some serious obstacles remain.

NATO's expansion to Russia's borders has angered Russian leaders in recent decades, and the U.S. plan for installing missile defense systems in Poland and the Czech Republic has intensified the chilliness in U.S.-Russian relations. Obama has said that these antimissile systems are only a response to the threat of an Iranian nuclear attack and that, if Iran agreed to forgo nuclear weapons, the systems would be unnecessary. But, at this point, Russian officials remain very suspicious of U.S. behavior and inclined to make the conditions of a START treaty dependent on a resolution of the missile defense issue.

Ratification of the CTBT is even more problematic. With U.S. Senate ratification of treaties requiring two-thirds support, a determined minority can kill just about any treaty. This is what happened in 1999, when, in an almost entirely party-line vote, a bloc of Republican senators defeated CTBT ratification. And it might well happen again this year. Although Democrats are enthusiastic about the CTBT, they will need 67 votes to push it through the Senate. And, thus far, not a single Republican senator has come out in favor of it.

An agreement by Iran to remain a non-nuclear power also remains uncertain. For one thing, the Iranian government might not be willing to stop short of developing nuclear weapons. Or the Israeli government might act preemptively or push the U.S. government into adopting a hard line. In addition, the U.S. Congress might demand concessions on other issues that the Iranian government won't make.

Finally, nuclear abolition remains far from certain. What if the U.S. government and others-despite their abolitionist rhetoric-simply aren't ready for this great a departure from their past policies? Also, isn't the level of popular mobilization for antinuclear action rather low by comparison to past periods of progress in nuclear disarmament? And what would happen to the goal of nuclear abolition if one or more of these specific actions-securing a new START treaty, CTBT ratification, and an agreement with Iran-resulted in failure?

Even so, it appears likely that, in the next few years, at least some nuclear disarmament efforts will prove fruitful. Moreover, the failure of one or more of them need not derail the overall movement toward a nuclear-free world. To avoid this situation, Kevin Martin, the executive director of Peace Action (the largest peace and disarmament organization in the United States), has proposed a leapfrog strategy. In addition to supporting specific disarmament measures, he has maintained, nuclear disarmament supporters should champion a U.S. government announcement, made at the nuclear Nonproliferation Treaty Review Conference of 2010 or before, that it is initiating multilateral negations for a treaty or convention to abolish nuclear weapons. After all, there is no reason to delay negotiation of such a treaty until all of the specific actions have been taken. Indeed, some might become part of such a treaty.

Overall, then, the United States and other nations are headed once more toward confronting the nuclear menace. Given the obstacles, progress might not be rapid. As Obama remarked in Prague, a world without nuclear weapons "will not be reached quickly. . . . It will take patience and persistence." But, for the first time in two decades, a serious effort is being made along these lines. And results seem likely to follow.