The recent tentative agreement with North Korea over its nuclear program illustrates how diplomacy can work even with the most unsavory of regimes. Unfortunately, it took the Bush administration more than six years to commit to diplomacy. During that needless delay North Korea developed and tested nuclear weapons -- weapons its leaders still have not agreed to dismantle. Had we engaged the North Koreans earlier, instead of calling them "evil" and talking about "regime change," we might have prevented them from going nuclear. We could have, and should have, negotiated a better agreement, and sooner.

As the International Atomic Energy Agency just confirmed, Iran has once again defied the international community and is moving forward with its nuclear program, yet the Bush administration seems committed to repeating the mistakes it made with North Korea. Rather than directly engaging the Iranians about their nuclear program, President Bush refuses to talk, except to make threats. He has moved ships to the Persian Gulf region and claims, with scant evidence, that Iran is helping Iraqi insurgents kill Americans. This is not a strategy for peace. It is a strategy for war -- a war that Congress has not authorized. Most of our allies, and most Americans, don't believe this president, who has repeatedly cried wolf.

Saber-rattling is not a good way to get the Iranians to cooperate. But it is a good way to start a new war -- a war that would be a disaster for the Middle East, for the United States and for the world. A war that, furthermore, would destroy what little remains of U.S. credibility in the community of nations.

A better approach would be for the United States to engage directly with the Iranians and to lead a global diplomatic offensive to prevent them from building nuclear weapons. We need tough, direct negotiations, not just with Iran but also with our allies, especially Russia, to get them to support us in presenting Iran with credible carrots and sticks.

No nation has ever been forced to renounce nuclear weapons, but many have chosen to do so. The Iranians will not end their nuclear program because we threaten them and call them names. They will renounce nukes because we convince them that they will be safer and more prosperous if they do that than if they don't. This feat will take more than threats and insults. It will take skillful American diplomatic leadership.

Diplomacy is more than just talking to people. It requires speaking credibly from a position of strength. As the U.S. ambassador to the United Nations, as energy secretary, as a member of Congress and as a diplomatic envoy, I have always believed in and worked to achieve tough, credible and direct negotiations with adversaries. To be tough, you need strong alliances and a strong military. And to be credible, you need a record of meaning what you say. By alienating our allies, overextending our military, making idle threats and antagonizing just about everyone, the Bush administration has undermined our diplomatic leverage.

We need to change course. Iran's nuclear program is a threat to peace, but it also presents an opportunity to start rebuilding America's credibility and leadership, which have been weakened by six years of incompetence.

This is no time for chest-beating and dangerous brinkmanship. It is time for alliance-building, direct engagement and tough face-to-face negotiations. For the United States to attack Iran without exhausting all diplomatic options would be a terrible mistake.

The writer, a Democrat, is governor of New Mexico and a presidential candidate.