With U.S. Senate ratification of the New START treaty on December 22, supporters of nuclear disarmament won an important victory. Signed by President Barack Obama and Russian President Dimitry Medvedev last April, the treaty commits the two nations to cut the number of their deployed strategic (i.e. long-range) nuclear warheads to 1550 each — a reduction of 30 percent in the number of these weapons of mass destruction. By providing for both a cutback in nuclear weapons and an elaborate inspection system to enforce it, New START is the most important nuclear disarmament treaty for a generation.

Nevertheless, the difficult battle to secure Senate ratification indicates that making further progress on nuclear disarmament will not be easy. Treaty ratification requires a positive vote by two-thirds of the Senate and, to secure the necessary Republican support, Obama promised nearly $185 billion over the next decade for “modernizing” the U.S. nuclear weapons production complex and nuclear weapons delivery vehicles. Even with this enormous concession to nuclear enthusiasts — a hefty “bribe,” in the view of unhappy arms control and disarmament organizations — Senator Jon Kyl, the Republican point man on the issue, continued to oppose New START and ultimately voted against it. So did most other Republican Senators, including Mitch McConnell (Senate Republican leader) and John McCain (the latest Republican presidential candidate). Leading candidates for the GOP presidential nomination in 2012, including Mitt Romney and Sarah Palin, also opposed the treaty. As a result, New START squeaked through the Senate by a narrow margin. With six additional Republicans entering the Senate in January, treaty ratification will become much harder.

So where do the possibilities for progress on nuclear disarmament lie in the future?

One obvious focus for action is ratification of the Comprehensive Test Ban Treaty (CTBT). Signed by the United States and most other nations in 1996, the treaty provides for a total ban on the nuclear explosions that serve as the basis for the development of new nuclear weapons. This ban would be enforced by an extensive international verification system. Republican opposition blocked Senate ratification of the CTBT in 1999, and President George W. Bush — hostile to this arms control measure and others — refused to resubmit the treaty. Nevertheless, President Obama has consistently supported ratification of the CTBT, and has promised to bring it before the Senate once again. After the bruising battle over the START Treaty and in the context of heightened Republican strength in the new Senate, however, he might now change his mind.

A more promising area for progress is a follow-up nuclear disarmament agreement between the United States and Russia. As these two nations possess the vast majority of the world’s nuclear weapons, other countries have long argued that, before progress can be made in reducing the arsenals of the other nuclear powers or blocking nuclear proliferation, the two nuclear giants must cut their nuclear stockpiles substantially. In fact, officials from both the United States and Russia have spoken of another round of START negotiations that would reduce their deployment of strategic warheads to 1,000 each. There is also pressure to cut the number of tactical nuclear weapons they possess — especially the very large numbers still maintained by Russia. Indeed, Republican opponents of the New START treaty seized on the tactical nuclear weapons issue to argue that the real need for a treaty lay in the tactical weapons area. Given their rhetorical stance, it might be useful to confront them with such a treaty.

Nevertheless, stumbling blocks remain to a new arms treaty with Russia. Not only are the Republicans likely to use their enhanced Senate strength to block its ratification, but the Russians might refuse to accept a new agreement. The apparent reason for Russian reluctance is U.S. government insistence upon deploying a missile defense system in Europe, on Russian borders. Although the Obama administration does not appear enthusiastic about missile defense, it has given way before Republican demands to install it. Conversely, if the administration bargains away missile defense in treaty negotiations with the Russians, it seems quite likely that Republicans will strongly oppose the treaty.

Perhaps the most promising area for disarmament progress doesn’t involve treaty negotiations or ratification, but simply blocking nuclear “modernization.” After all, Senator Kyl and most Republicans didn’t accept the “bribe” offered them, but continued to oppose the New START treaty. Why, then, should the Obama administration follow through on providing $185 billion for refurbishing the U.S. nuclear weapons complex, especially when such a program so clearly flies in the face of his pledge to work for a nuclear weapons-free world?

Even if the administration sticks to its “modernization” line, however, there is no reason for other forces, inside and outside Congress, to do so. Over the coming years, in the midst of a huge debate on budgetary priorities, there will be a fierce battle over scarce government resources. Are angry seniors (concerned about cutbacks in Social Security and Medicare), parents, students, and teachers (concerned about cutbacks in education), the hungry, homeless, and unemployed (concerned about the collapse of the social safety net), and other groups (facing serious attacks on their living standards) going to welcome spending $185 billion for new nuclear weapons facilities? Certainly groups with domestic spending priorities, plus peace and disarmament groups, are going to press congress to move the money from funding wars and weapons to meeting social needs. Perhaps they will succeed.

Thus, in the next two years, the Republicans may end up choking off the opportunities for negotiated disarmament and opening the floodgates to unilateral action.

Lawrence Wittner is Professor of History emeritus at the State University of New York/Albany. His latest book is “Confronting the Bomb: A Short History of the World Nuclear Disarmament Movement” (Stanford University Press).