PARIS, March 13 — After trying for years to prevent having its nuclear program judged in the United Nations Security Council, Iran has shifted course and decided to confront the Council head on.
Iran is gambling that the 15 members, who plan to take up the Iranian dossier this week for the first time, will be too divided to inflict meaningful punishment.
Sanctions against Iran, the second largest oil producer in OPEC, could further destabilize the oil markets. Military force, at least for the moment, is unlikely, with American troops stretched thin in Iraq and Afghanistan.
So Iran's leaders have stopped trying to woo the world and now say they want the process to take its course.
"Let the Security Council review the dossier directly," President Mahmoud Ahmadinejad told reporters in January, defending the reopening of the uranium enrichment facility in Natanz for what Iran describes as research. "Since we have a clear logic and we act according to the law, we are not worried."
In Tehran on Monday, Mr. Ahmadinejad portrayed Iran's position not as obstinate or rigid but as a reflection of strength. "We know well that a country's backing down one iota on its undeniable rights is the same as losing everything," state television quoted him as saying. "We will not bend to a few countries' threats, as their demands for giving up our nation's rights are unfair and cruel."
Ayatollah Ali Khamenei, Iran's supreme leader and the country's ultimate authority, who once stood before the United Nations and branded it "a paper factory for issuing worthless and ineffective orders," has also endorsed the strategy. In remarks to leading clerics on Thursday, he vowed to "resist any pressure and threat," adding, "If Iran quits now, the case will not be over."
Iran has never had much use for the Security Council.
When Saddam Hussein invaded Iran in 1980, the Council at first did not even call for a cease-fire or the withdrawal of the Iraqi troops to the border.
When Iraq used chemical weapons against Iranian soldiers later in the decade — the first verified use of chemical weapons since World War I — the Council refused to impose sanctions.
Iran had only itself to blame, the Council seemed to say. The country was seen as a renegade state that could not be trusted. It violated international law when it seized the American Embassy in 1979 and held diplomats hostage. It continued the war against Iraq for years after Mr. Hussein brought his soldiers home.
But beginning in 2003, a few months after Iran's clandestine nuclear sites were uncovered, Tehran began to take whatever small conciliatory measures were necessary to keep its nuclear program off the Security Council's agenda.
Avoiding action in that forum was at the heart of Iran's decision to open negotiations with France, Britain and Germany in 2003 and to allow inspectors from the International Atomic Energy Agency access to its nuclear sites, according to Hassan Rowhani, who was replaced as Iran's chief nuclear negotiator after Mr. Ahmadinejad took office last year.
"At that time, the United States was at the height of its arrogance, and our country was not yet ready to go to the U.N. Security Council," Mr. Rowhani said at a closed-door session of Iran's ideological policy makers in September, as he was leaving his post.
Consideration of Iran's case by the Council would give the United States more power over Iran's fate, reduce the influence of the Europeans and expose Iran's missile program to new scrutiny, Mr. Rowhani said.
"The most important promise" the Europeans gave Iran, he said, "was that they would stand firm against attempts to take this case to the U.N. Security Council."
The speech was published late last year in a Persian-language journal, Rahbord.
Iran's nuclear strategy had been based on keeping the program secret, Mr. Rowhani said, and once that secrecy was shattered, the country became vulnerable to pressure. Iran, he said, had "no choice" except to enter into negotiations with the Europeans and to open its nuclear facilities to inspectors.
Under a November 2004 agreement with the Europeans, Iran pledged to freeze enrichment-related activities as long as the two sides were negotiating a long-term package of incentives for the country.
But in a remarkable admission, Mr. Rowhani suggested in his speech that Iran had used the negotiations with the Europeans to dupe them. He boasted that while negotiations were continuing, Iran managed to master a key stage in the nuclear fuel process — the conversion of uranium yellowcake at its Isfahan plant.
"While we were talking with the Europeans in Tehran, we were installing equipment in parts of the facility in Isfahan, but we still had a long way to go to complete the project," he said. "In fact, by creating a calm environment, we were able to complete the work on Isfahan."
As a result of the negotiations with Europe, he added, "We are in fact much more prepared to go to the U.N. Security Council."
The view that Iran is ready to take on the Council is not wholeheartedly embraced inside Iran. While Iran's decision to continue its uranium enrichment activities is universally defended, some public figures have criticized the confrontational tone.
Simply being investigated by the Council is enough to erode international confidence in Iran, some analysts say, with damaging repercussions.
"Even if political measures are not taken against us, the country's political prestige will be jeopardized," Ahmad Shirzad, a reformist politician and former legislator, said last month. "There will also be major effects in the economy. Investors will move their capital to safe places and there will be a brain drain."
Particularly striking has been criticism by Mohammad Khatami, the former president. "There will be bad consequences if our case is sent to the Security Council," he predicted last month. "It will not only affect our economy. Our right to nuclear energy might also be affected."