CAIRO—Until Iran's current political crisis, Iranian experts largely agreed that the Islamic republic wanted to develop the capacity to build nuclear weapons, without actually producing them.

Now, not everyone is so sure.

The main reason for the shift in thinking is the rise of the Iranian Revolutionary Guards Corps as the most powerful decision-making bloc in the county. But the change is also a result of the political struggle among the elite, which has upended previous assessments about Iran's decision-making process, silenced more pragmatic voices and made it nearly impossible for anyone to support nuclear cooperation without being accused of capitulating to the West.

This move toward a harder line has stymied President Barack Obama's attempts to open a new channel of communication with the Iranian leadership. And now, having set a year-end deadline for Iran to cooperate, the United States and its Western allies seem likely to seek to impose tougher sanctions on Iran, a step that some analysts fear could enable the more radical forces to monopolize power, at least in the short term.

“;A Revolutionary Guards-dominated state that we have witnessed since the presidential election has proven to be a lot less prudent, and a whole lot more violent, than what was the ordinary behavior of the Islamic Republic of Iran before,”; said Rasool Nafisi, an Iran researcher in Virginia who co-wrote a report on the Revolutionary Guards for the RAND Corp. “;One should calculate the impact of such a state on nuclear development with more caution.”;

That is not to say that Iran is necessarily preparing to drop out of the Nuclear Nonproliferation Treaty or to make a bomb and declare itself a nuclear weapons state, the way North Korea did. But Iranians who support full-on confrontation with the West have the upper hand in the country's public debate and decision making at the moment, Iran experts and European diplomats said.

Hossein Shariatmadari, editor of Kayhan, the newspaper that serves as a bulletin board for Iran's supreme leader and the most radical forces in the Revolutionary Guards, wrote last month that “;under the circumstances, is it possible to still argue that Iran's membership”; in the treaty is prudent? “;Isn't it wise, honorable and expedient to withdraw from the treaty instead?”; he continued “;Why not?!”;

It is not clear what the West can do about the problem.

While the type of new sanctions under consideration and the willingness of China and Russia to impose them are still uncertain, some Iran experts and diplomats are skeptical that they can reverse the country's evolution toward a more militarized and radical leadership. Some fear that a sharper confrontation with the West could even accelerate that process.

“;The idea, of course, is to see whether sanctions can contribute to setting in motion an internal political shift,”; said a European diplomat with many years of service in Iran who insisted on anonymity in keeping with diplomatic protocol. “;But that is doubtful.”; The diplomat said the government had shifted from cynical authoritarianism to radical repression.

Iran has not so far embraced the North Korea model of renouncing the nonproliferation treaty and bargaining with the outside world as a self-declared nuclear weapons state. But there are concerns that the leadership in Tehran is feeling so paranoid and vulnerable because of the internal divisions, that if pushed, it might head in that direction.

“;The aftermath of the election has isolated them,”; said Muhammad Sahimi, an Iran expert who closely follows events through a network of friends there. “;They are under tremendous pressure, both internally and externally. They also are not sure whether they can count on unified support of the people if attacked militarily, due to what has happened.”;

Iran would still have a great deal to lose by formally dropping out of the treaty and declining to negotiate with the West, and some experts say they still doubt that the embattled leadership will take that step.

Pulling out would undermine Iran's central claim that its nuclear program is peaceful in nature. It might also erode the willingness of China and Russia to continue to support Iran at the U.N. Security Council, and it might encourage Israel to wage a military strike with the silent approval of the West, experts said. It would also commit Iran to the most radical path and use up a powerful point of leverage for future negotiations, they said.

“;As long as Tehran can cast the issue as one of imperialists trying to deny their rights to nuclear technology, Iran gets the support of a significant swath of the developing world,”; said Mark Fitzpatrick, a senior fellow for nonproliferation with the International Institute for Strategic Studies in London.

In the best of times, reading Iran's intentions is difficult, because while there were elected institutions full of public debate, the most important decisions were forged in secret by the supreme leader, Ayatollah Ali Khamenei, his aides and a core of the political elite. But the political crisis appears to have diminished the process of consultation by neutralizing some of the nation's most powerful figures, including Ali Akbar Hashemi Rafsanjani, a former president, and on the nuclear issue even the president, Mahmoud Ahmadinejad.

In the opportunistic, factionalized post-election environment, Ahmadinejad has emerged as a voice of pragmatism on the nuclear issue, in relative terms, while so-called pragmatic conservatives, like Ali Larijani, the speaker of Parliament, and even reformers, like Mir Hussein Moussavi, who lost the election to Ahmadinejad, have opposed an agreement with the West that was under discussion in the fall.

Ahmadinejad, who has said that it is time to cooperate, seemed to favor a deal struck by Iranian negotiators during talks in Geneva in October. They agreed to send much of Iran's low-enriched uranium to Russia, and then France, where it would be converted to fuel rods. The rods, which could be used to power a medical reactor, but would be difficult to covert into weapons fuel, would then be sent to Iran. The West accepted the idea because it would have delayed, by about a year, Iran's ability to make a bomb.

But once the deal was announced, Ahmadinejad's political enemies back home attacked him, eager to undermine his credibility and legitimacy with the same blunt instrument he had used for so long against his political rivals, the nuclear issue.

“;Given divisions within the ranks—the first time that real power brokers are divided, and that is something Obama has achieved with the Geneva deal much more so than street protests—the leadership knows that it does not want to conclude a deal,”; said a Washington-based Iran expert who asked not to be identified because he sometimes visits Iran.

In this environment, Larijani, who is close to the supreme leader and whose family has close ties to the most influential clergy members in the country, raised the prospect of abandoning the Nuclear Nonproliferation Treaty altogether.

“;What use is there to be a part of the NPT when it cannot even defend the rights of its members?”; Larijani said, according to Iran's semi-official ILNA news service. “;Those who seek peaceful nuclear technology should continue to do so without any attention to the treaty because it does nothing but complicate matters even more.”;

Ahmadinejad has tried to regroup, with his government insisting that it is still ready to agree to turn over much of its low-enriched uranium, but on its own terms, which the West has already rejected. The government has also insisted that Iran will not withdraw from the treaty.

In the past, Iran's equivocating would be seen as a strategy aimed at dividing the West from Russia and China. But while that is probably part of the explanation, there is a general sense that it also reflects the inability of such a fractured nation to reach a firm decision on the issue. The question the West needs to calculate is, What will that decision ultimately be?

“;A majority of analysts believe that Iran will stop short of making a bomb, but would like to be bomb-ready,”; said Nafisi, the researcher in Virginia. “;But I think it depends a lot on the political situation when Iran has enough fissile materials to build a bomb.”;