The United Nations Security Council on Thursday unanimously adopted a resolution "to seek a safer world for all and create the conditions for a world without nuclear weapons."

This strong and historic resolution was adopted at the first UNSC summit on nuclear nonproliferation and nuclear disarmament, attended by the leaders of both the five permanent UNSC member states — the United States, Russia, Britain, France, and China, which are nuclear-weapons states — and the nonpermanent member states, which include Japan. The resolution is an important step toward making efforts to create a nuclear weapons-free world irreversible.

It is significant that the resolution was sponsored by the U.S., since the U.S. and Russia combined possess some 90 percent of the world's nuclear warheads. Moreover, the summit was chaired by Mr. Barack Obama, who became the first U.S. president to chair a meeting of the 15-nation council.

As Mr. Obama stated, the resolution "enshrines our shared commitment to the goal of a world without nuclear weapons" and "brings Security Council agreement on a broad framework for action to reduce nuclear dangers as we work toward that goal."

In his April speech in Prague, Mr. Obama underlined the right of people everywhere to live free from the fear of nuclear weapons in the 21st century and expressed America's commitment to seek the peace and security of a world without nuclear weapons. It is clear that this speech helped revive global efforts for nuclear disarmament. His recent decision to cancel a missile-defense program in Poland and the Czech Republic also provides a good chance for the U.S. and Russia to conclude a treaty to succeed START-1 (Strategic Arms Reduction Treaty-1) by yearend.

In the UNSC meeting, Mr. Obama correctly described the dangers the world now faces. He said, "Although we averted a nuclear nightmare during the Cold War, we now face proliferation of a scope and complexity that demands new strategies and new approaches."

The resolution calls on states that are not parties to the Nuclear Nonproliferation Treaty (NPT) to join it and urges NPT member states to cooperate so that the NPT Review Conference in May 2010 can "strengthen the treaty and set realistic and achievable goals in the treaty's three pillars: nonproliferation, the peaceful use of nuclear energy and disarmament."

It also calls on the Conference on Disarmament in Geneva to negotiate a treaty to ban production of fissile material for nuclear weapons or other nuclear devices as soon as possible.

In an apparent reference to North Korea and Iran, the resolution "expresses particular concern at the current major challenges to the nonproliferation regime" and demands that U.N. member states fully comply with past UNSC resolutions that imposed sanctions against the two countries.

Importantly, the resolution calls on the five nuclear weapons states to fulfill their NPT obligations by undertaking "to pursue negotiations in good faith on effective measures relating to nuclear arms reduction and disarmament and on a treaty on general and complete disarmament under strict and effective international control," and invites all other nations to join in this endeavor. If the five states — the U.S., Russia, Britain, France, and China — make sincere efforts to meet the call, they will acquire greater moral suasion in getting other states with nuclear weapons ambitions to give them up.

It also calls on all states to refrain from conducting a nuclear test explosion and to join the 1996 Comprehensive Test Ban Treaty to bring the treaty into force at an early date. For the treaty to go into force, 44 more states have to ratify it. Of these countries, nine — the U.S., China, India, Pakistan, Iran, North Korea, Israel, Egypt and Indonesia — have not yet either signed or ratified it. In an encouraging sign, the U.S. for the first time in 10 years attended a high-level New York conference on the CTBT on Thursday and Friday. The U.S.' ratification of the treaty could induce China to also ratify it.

In addressing the UNSC summit, Japanese Prime Minister Yukio Hatoyama renewed Japan's commitment to the three-point nonnuclear principle of not making, not possessing and not allowing the bringing in of nuclear weapons. He also declared that Japan, the only country that has suffered from atomic bombings, will not go nuclear. Although Japan has the potential to develop nuclear weapons, Mr. Hatoyama said, it wants to prevent the vicious cycle of a nuclear-arms race. This is a realistic and reasonable decision. World leaders should heed his call to visit Hiroshima and Nagasaki to learn firsthand the cruel effects of nuclear weapons.

Mr. Obama said, "The next 12 months will be absolutely critical in determining whether this resolution and our overall efforts to stop the spread and use of nuclear weapons are successful." The time has come for states with nuclear weapons as well as those without them to act in earnest.