In addition, the United States can rely on other deterrents to safeguard security and strategic interests and ensure it maintains its position ahead of other countries. In February, U.S. Vice President Joe Biden said in a speech at the National Defense University in Washington, the United States had long relied on nuclear weapons to deter its enemies, but with scientific and technological developments, it could now achieve the same goal without using nuclear weapons.

What's more, the United States thought restoring its leadership in the world nuclear disarmament campaign would help it re-integrate into the world and strengthen its soft power. As nuclear weapons demonstrated the trend of proliferation, an ever-enlarging nuclear shadow required Obama put nuclear disarmament on top of his agenda.

The Americans were serious about the nuclear security issue. Obama announced steps to implement the plan of a nuclear-free world. For instance, the United States would conclude a new strategic arms reduction treaty through negotiation with Russia to cut dramatically the nuclear weapons arsenals of the two countries. It would also urge its Congress to approve the CTBT as quickly as possible, and strive to strengthen the NPT with other countries, including intensifying verification, strengthening sanctions against countries violating it and seeking a new mechanism for the peaceful use of nuclear energy. Further measures included ensuring fissile materials that can be used for nuclear weapons production will not be spread, and holding a world summit on nuclear security.

In addition, the United States also sought to reach an international treaty aimed to end the production of fissile materials, to ensure terrorists could never acquire nuclear weapons or nuclear materials.

The Washington Nuclear Security Summit on April 12-13 is a very important component of the whole plan.

Obama's trilogy

The purpose of the Washington summit is to call on all countries to strengthen protection for nuclear materials and nuclear weapons, and to crack down on smuggling and underground nuclear markets. About 40 countries with abiding interests in the nuclear security issue are to participate in the summit. This is a significant part of Obama's nuclear control policy which aims to seek multilateral solutions to the nuclear security issue.

The Washington summit is just one part of Obama's trilogy for a nuclear-free world in 2010.

The Nuclear Posture Review released on April 6 was the first part. It announced the United States would reduce nuclear weapons, stop the development of new weapons and reduce their role in its national security strategy. But it is noteworthy it did not promise no preemptive use. This showed the United States' new nuclear strategy position and policy direction.

The nuclear security summit in Washing-ton is the second part. Then there comes the third part—reviewing the NPT in May.

With these moves, Obama intends to include nuclear disarmament in a strengthened non-proliferation system. The trilogy will constitute the peak moment of world nuclear security in 2010. It will definitely be a brilliant landmark in the history of nuclear disarmament and non-proliferation. It means a new peak for the Global Zero movement and will contribute to the birth of a new pattern of international relations and strategies.

From the summit and related events, we have good reason to believe the world will definitely change again in the 21st century on account of nuclear weaponry.

For one thing, the prospect of nuclear terrorism is truly horrible. We must prevent it from becoming true. For another, nuclear weapons are no longer weapons only of big countries. Big countries, therefore, will strengthen cooperation, seeking to establish a new nuclear security system.

Experts point out big countries acquired nuclear weapons in the 20th century because of their destructive capability, and also because few countries had the technology at that time. But in the 21st century, not only small countries but also non-state groups and even terrorist organizations find it possible to obtain them. This is a problem changing the world.

Therefore, in the light of their own interests, big countries must consider reducing dependence on nuclear weapons and pursue the goal of Global Zero. Based on this analysis, a new nuclear non-proliferation and nuclear disarmament system consistent with the 21st century situation must be built. And this system must be led by major members of the nuclear club—the United States, Russia, Britain, France and China.

If the world of the 20th century changed because of the possession of nuclear weapons, then the world of the 21st century will change with the elimination of nuclear weapons. International cooperation is a must. Adjustments in big countries' nuclear security policies and strategies are inevitable. International systems and mechanisms concerned with these matters will surely be strengthened.

China's role

The international community has long realized China's participation is essential when addressing issues of world peace, development and cooperation. Without the presence of Chinese leaders, the outcome of any world summit will certainly be far less effective. In terms of the nuclear security issue, China's participation is also essential.

China attaches great importance to both nuclear security and multilateral summit diplomacy. Last September, Chinese President Hu Jintao attended the UN Security Council Summit on Nuclear Non-proliferation and Nuclear Disarmament. This year, he is scheduled to attend the Nuclear Security Summit in Washington, D.C. This clearly shows China's active stance and policy.

As a permanent member of the UN Security Council and a responsible, peace-loving country, China proposes all nations work together to establish a harmonious world with lasting peace and common prosperity. It has always pursued a positive stance in maintaining global nuclear security. It has been opposed to nuclear proliferation and nuclear terrorism, actively promoted cooperation, and made great efforts to safeguard the security of all countries.

The author is deputy director of the Department of Global Strategy at the China Institute of International Studies