The fight-to-the death that the president is poised to launch against Saddam Hussein's regime will send a tsunami of destabilization throughout the Middle East. But beyond that, if this war is not authorized by the UN Security Council, it threatens to unravel not just the 58-year-old UN system, but the whole web of interstate relations that has grown up through the past four centuries.
We would be catapulted back to a Hobbesian world of "might makes right" in international affairs. In such a world, as Hobbes warned us, human life can only be "nasty, brutish, and short."
The threat to the UN system is already dire. Yes, the UN has made mistakes and still has many shortcomings. And yes, the US has sometimes had rocky relations with the UN over the years. But for the vast majority of the world's people, the UN represents an ideal of national equality, and embodies their desire that international conflicts be resolved without war. In thousands of places around the world, the UN delivers basic human services - nutrition, healthcare, water management, shelter - that governments are too weak or impoverished to provide. In explosive hot spots - including the Kuwait-Iraq border - UN peacekeepers help monitor and defuse otherwise deadly tensions.
President Bush has repeatedly said, "When it comes to our security, we don't need anybody's permission." That can only mean he's prepared to go to war against Iraq even without Security Council authorization. Make no mistake: If the president does that, he will start a cascade of actions and counteractions that could unravel the UN, all its good works and the ideals it represents, within months - not years.
There are many world bodies that depend on the essential political compact embodied in the UN charter. The unraveling of that compact would have a devastating ripple effect. The costs would not be to UN feeding programs and peacekeepers. The International Atomic Energy Agency is the UN body that keeps a lid on suspect nuclear programs around the world. An eviscerated UN? An eviscerated IAEA. The International Monetary Fund, and the World Trade Organization are UN-related bodies that would also be undermined. An eviscerated UN? An eviscerated IMF and WTO - and much less predictability and order in the international economy.
Is Mr. Bush prepared to risk such outcomes? UN Secretary-General Kofi Annan has pointed out that a US-led war not authorized by the Security Council, "would not be in conformity with the [UN] Charter," and that "the legitimacy ... for any such action will be seriously impaired." But Mr. Annan, in his usual low-key way, understates the risk. The US is not "just another" UN member-state. It is the world's preeminent power, dominating the world's strategic balance and economy. If a country as powerful as the US bucks the UN system in such a major way, then the UN system itself will be at risk. With due respect to the Gabonese, the US is not Gabon.
We have a precedent for the unraveling of an international organization: It happened to the League of Nations in the late 1930s. Unprecedented brutality ensued. That unraveling took a number of years. The one now threatened could happen in months.
But today's unraveling threatens elements of international stability that go back even further. Given Bush's seeming determination to remake the world in the American image - starting with Iraq - he now threatens to plunge the world back to the early 1600s. In that time of ferment in Northern Europe, numerous local princes tried to impose their beliefs on their neighbors in the conflict known as the Thirty Years' War. (Thomas Hobbes lived through that war. He knew what "nasty, brutish, and short" lives were like.)
That conflict ended with the Treaty of Westphalia. The treaty's genius lay in the pluralistic, "live and let live" attitude it embodied regarding belief-system differences among states. The signatory princes promised not to try to impose their own beliefs on their neighbors - though they were still free to impose them on their own subjects.
Liberals have criticized Westphalia because its norm of international "non-intervention" allows a dictator like Hussein to brutalize his subjects without any effective international effort to stop him. But the nonintervention norm has also, crucially, allowed nations with indigenous democratic movements to democratize. Without it, infant democracies would all have been strangled by brutal neighbors.
Today, Bush's many declarations, and the unauthorized war he threatens against Iraq, pose a head-on challenge to the pluralism of the Westphalian system. He expresses a messianic conviction that he knows what's best for everyone in the world, along with an insistence that he needs no one's permission to impose it.
Many Americans remember a previous effort by a well-meaning president to use the US military's dominant position to forcibly impose democracy on another country. That was President Johnson, in 1968, in Vietnam.
In 2003, a similar effort to impose democracy on Iraq through force can similarly be expected to fail. This time though, the cost to global stability and human well-being would be much higher. Mr. President, turn back!
• Helena Cobban is the author of five books on international issues.