It is perhaps the least talked about and most worrying irony of our time. The United States has a massive defense budget, but spends relatively little addressing the most immediate danger to humanity.

Global security is vital to family life, the growth of business, the wise husbanding of resources and the environment. And yet, all our hopes and plans for the future exist under the shadow of a catastrophic threat – one that could kill millions of people in a few moments and leave civilization in shambles.

Although there are other significant threats, such as global warming and infectious diseases, it is nuclear weapons that are the greatest immediate danger confronting our species. We must stop ignoring this threat and start providing leadership to eliminate nuclear arsenals around the globe.

Let’s look at some of the facts about nuclear weapons. They are the only weapon capable of destroying civilization and the human species. They kill indiscriminately, making them equal opportunity destroyers. In the hands of terrorists, they could destroy a country as powerful as the United States. A nuclear 9/11 could have resulted in deaths exceeding one million and the collapse of the US and world economies.

There are currently some 27,000 nuclear weapons in the world, and 12,000 of these are deployed. Of these, 3,500 nuclear weapons are on hair-trigger alert, ready to be fired in moments.

Nine countries currently possess nuclear weapons: the United States, Russia, UK, France, China, Israel, India, Pakistan and North Korea. More than 95 percent of the nuclear weapons in the world are in the arsenals of the US and Russia. The UK, France, China and Israel are estimated to have arsenals numbering a few hundred each. India and Pakistan are thought to have arsenals under 100, and North Korea to have up to 12 nuclear weapons. As many as 35 other countries have the technological capability to become nuclear weapons states, including Japan, South Korea, Taiwan, Brazil, Iran and Egypt.

Nuclear weapons give a state sudden clout in the international system. India, Pakistan and North Korea all increased their stature in the international system after testing nuclear weapons. Recently, Brazilian President Luiz Inacio Lula da Silva emphasized the perceived prestige that nuclear weapons potential gives a country. He said: “Brazil could rank among those few nations in the world with a command of uranium enrichment technology, and I think we will be more highly valued as a nation — as the power we wish to be.”

Nearly all countries in the world are parties to the Nuclear Non-Proliferation Treaty (NPT). Only three countries have not signed the treaty: Israel, India and Pakistan. A fourth country, North Korea, withdrew from the NPT in 2003. All of these countries have developed nuclear arsenals.

The NPT obligates the nuclear weapons states that are parties to the treaty to engage in good faith negotiations for nuclear disarmament. The International Court of Justice has interpreted this to mean that negotiations must be concluded “leading to nuclear disarmament in all its aspects.”

As the world’s only remaining superpower, the United States can lead the way in fulfilling this obligation. It has failed to do so. The US missile defense program has been provocative to other countries, particularly Russia and China, and has resulted in these countries improving their offensive nuclear capabilities. The US has also sought to upgrade and improve its nuclear arsenal, and has proposed replacing every thermonuclear weapon in the US arsenal with the so-called Reliable Replacement Warhead. The US has, in effect, said to the world that it intends to rely upon its nuclear arsenal indefinitely.

In addition, the US has failed to provide legally binding security assurances that it will not use nuclear weapons against non-nuclear weapons states. In fact, the US indicated in its 2001 Nuclear Posture Review that it was developing contingency plans for the use of nuclear weapons against seven countries – two nuclear weapons states (Russia and China) and five non-nuclear weapons states (Iraq, Iran, Syria, Libya and North Korea, which at the time was not thought to have nuclear weapons).

US nuclear policy undermines the security of its people. The more the US relies on nuclear weapons, the more other countries will do so. Former United Nations Secretary General Kofi Annan has stated: “The more that those states that already have [nuclear weapons] increase their arsenals, or insist that such weapons are essential to their national security, the more other states feel that they too must have them for their security.” Reliance on nuclear weapons will assure their proliferation.

The more nuclear weapons in the world, the more likely they will end up in the hands of terrorist extremists incapable of being deterred. The longer nations rely on nuclear weapons for security, the more likely it is that they will be used, by accident or design.

The US needs to work urgently for a treaty for the phased, verifiable, irreversible elimination of nuclear weapons under strict international control, just as we have already done with chemical and biological weapons. To do this requires political will, which has not been demonstrated by the current US administration. Continuing with existing US nuclear policies is a recipe for disaster. The Cold War ended more than15 years ago, and new problems now confront humanity. It is time for a drastic change in US nuclear policy – change that will require strong and effective leadership.

David Krieger is the President of the Nuclear Age Peace Foundation (