LAST FRIDAY, Britain, France and Germany -- the three European nations that had been negotiating the future of the Iranian nuclear program -- put their final proposal on the table. Among other things, they offered Iran a role in the discussion of regional security issues, a trade and cooperation agreement, and technical advice on everything from seismology to aircraft safety. Most important, they promised Iran access to nuclear fuel and to nuclear technology that would be more than adequate, negotiators said, for the peaceful generation of nuclear power. In exchange, they asked Iran to cease enriching uranium -- a process that can lead to the production of nuclear weapons -- and to allow regular inspections of all Iranian nuclear facilities.
In making their proposal, the Europeans were clear about its significance. Had Iran agreed to the proposal, negotiators said, the move would have been widely understood as a sign that the Iranian government wanted a responsible role in the international community and that Iran's nuclear program really was intended for peaceful purposes only. The choice, as some put it, was between "jobs and bombs": Does Iran prefer to be isolated from the rest of the world, economically and politically, or does Iran want to give up its nuclear ambitions and become part of the international economy?
Yet on Saturday, Iran turned down the proposal. Now there is no further room for obfuscation, and no further reason to give Iranians the benefit of the doubt: The real aim of the Iranian nuclear program is nuclear weapons, not electric power. Those in Washington and elsewhere who have always believed that the Iranians want nuclear weapons have a right to feel that their skepticism was justified. Nevertheless, the experience of letting the Europeans do it their way, offering trade and economic incentives before bringing in sanctions or making any military threats, has been enormously important. Given both the history of flawed U.S. intelligence reporting on nuclear programs, and the fact that recent estimates place Iranian nuclear weapons six to 10 years in the future, it would have been extremely difficult for the United States on its own to get the rest of the world to agree on any sanctions regime. Now, any steps taken to prevent Iran from getting nuclear weapons will have international credibility.
What remains to be seen is whether the Europeans will come through, as they have promised they would, with a tough-minded push for sanctions. So far, so good: Today, the International Atomic Energy Agency is to hold an emergency session to discuss the Iranian nuclear program, and most expect the IAEA to eventually refer the issue to the U.N. Security Council. But the real test is long-term. E.U. and U.S. leaders should prepare a program of serious economic, technological and military sanctions to back up the United Nations' statements. The United States should also continue to endorse the European proposal, which explicitly recognizes Iran's right to a peaceful nuclear program, giving Iran further incentive to choose "jobs" over "bombs." All involved must also start speaking to other countries -- China, Russia, Japan -- to build international momentum.
The conclusion of these talks means that there is no excuse for Europe and the United States not to act in tandem; neither should they take any option off the table. It is no longer possible to consider the Iranian nuclear threat as anything but deadly serious.