Monday’s North Korean nuclear test was a dramatic reminder of the challenges to eliminating nuclear weapons world-wide. President Barack Obama has stated that he intends to pursue this goal while maintaining a reliable nuclear deterrent for the United States and its allies. But achieving nuclear abolition will likely require many years.

Indeed, it is difficult to envision the necessary geopolitical conditions that would permit even approaching that goal. Unless the U.S. and its partners re-energize international efforts to lessen the present dangers of nuclear proliferation and nuclear terrorism, they will never have the hope of reaching this long-term objective.

An effective strategy to reduce nuclear dangers must build on five pillars: revitalizing strategic dialogue with nuclear-armed powers, particularly Russia and China; strengthening the international nuclear nonproliferation regime; reaffirming the protection of the U.S. nuclear umbrella to our allies; maintaining the credibility of the U.S. nuclear deterrent; and implementing best security practices for nuclear weapons and weapons-usable materials worldwide.

With thousands of U.S. and Russian warheads still deployed, the threat of a nuclear war through strategic miscalculation is not entirely removed. Thankfully, Russia has neither shown nor threatened such intent against the U.S. The two nations cooperated through much of the post-Cold War period on reducing nuclear arsenals and curbing nuclear proliferation. But given the recent chill in U.S.-Russia relations — a result of NATO expansion efforts and missile-defense systems in Poland and the Czech Republic — the relationship faces significant challenges.

In order to “press the reset button” with Russia, in the words of Vice President Joe Biden, the U.S. needs to base strategic dialogue on the common interests of stopping nuclear proliferation, preventing nuclear terrorism, and ensuring the peaceful use of nuclear energy. The U.S. and Russia should conduct a joint threat assessment as a prerequisite to renewed arms control. In tandem, the U.S. and China should discuss their threat perceptions and seek greater cooperation on nuclear security and stability.

The spread of weapons-usable nuclear technologies may push the world to a dangerous tipping point. North Korea — despite nearly universal opposition — has developed a small nuclear arsenal and on Monday demonstrated its capability with a successful nuclear test. Iran claims to be developing a peaceful nuclear program but this is hard to believe. Partly in response to Iran, other Middle Eastern states, like Turkey and Egypt, are beginning to develop nuclear-power programs.

To prevent further proliferation, the Obama administration needs to leverage the next 12 months in the run-up to the May 2010 Nonproliferation Treaty Review Conference. The U.S. must redouble global efforts to enact the Comprehensive Test Ban Treaty on nuclear weapons, call for a ban on the production of fissile material for weapons, and provide sustainable resources to the International Atomic Energy Agency — the world’s “nuclear watchdog.”

In the meantime, as Mr. Obama has stated, the U.S. should maintain a safe, secure and reliable nuclear deterrent for itself and its allies. This deterrent should be adequately funded and staffed with top-notch managers, scientists and engineers. The administration should also decide whether to replace existing nuclear warheads with redesigned warheads or to increase programs to extend their operational lives on a case-by-case basis, weighing heavily recommendations from the weapons lab responsible for the warheads in question.

Another critical concern is the massive global stockpile of weapons-usable fissile material that could fuel thousands of nuclear explosives. The more states that have fissile material, the greater the chances of it falling into the hands of terrorists. Laudably, the Obama administration has committed to work with international partners to secure all vulnerable nuclear materials within four years. This ambitious agenda will require development of much better security practices and a cooperative effort among dozens of countries.

The dangers of nuclear proliferation and nuclear terrorism are real and imminent. Any serious effort to combat them will require the leadership of the United States.

This article was originally published in the Wall Street Journal

William Perry, a former secretary of defense, and Mr. Scowcroft, a former national security adviser, are the co-chairs of the Council on Foreign Relations-sponsored Independent Task Force on U.S. nuclear weapons policy. Mr. Ferguson, a senior fellow at the Council on Foreign Relations, is the project director.