The United States and its European allies have offered Iran a package of incentives to get Tehran to abandon any ambition to build nuclear weapons.  Iran has not rejected the package outright, but is standing firm against any preconditions for talks.  Iran's tough stance is an apparent reflection of the political muscle of Iran's president after only one year in office.

Determining who is making policy in Tehran on the nuclear issue is difficult to gauge.  Decision-making in Iran is an opaque process, and analysts must decipher the Iranian leadership just as a generation of analysts before tried to read the thinking of the Politburo of the now-vanished Soviet Union.

Hooshang Amirahmadi, director of Rutgers University's Center for Middle Eastern Studies, believes there are several competing centers of power in Iran.  He says decisions about something as critical as the nuclear issue are reached by consensus, but that the final say still rests with Supreme Leader Ayatollah Ali Khamenei.

"Given the structure of the regime, it will be the (supreme) leader, it will be Ahmadinejad, it will be (Hashemi) Rafsanjani, it will be the national security council, it is the parliament," Amirahmadi says. "I think it's a joint decision.  They all have accepted this road, except I think the last call will always come from the leader so long as he's there."

Analysts say President Mahmoud Ahmadinejad seems to be wielding considerable authority on the issue.  Hooshang Amirahmadi says President Ahmadinejad is using presidential power far more effectively than any of his predecessors, including the reformist-minded Mohammad Khatemi.

"This man has used every piece of the power the presidency has," Amirahmadi says. "And because he has the right wing and military people behind him, not as a commander but just as a friend, he is obviously acting more powerfully than any previous president -- certainly more powerfully than Khatemi."

Ahmadinejad was the mayor of Tehran and a local politician with no national experience when he stunned observers by winning the presidential election one year ago.  Ken Katzman, an Iran analyst at the nonpartisan Congressional Research Service, says Khatemi took a much more cautious approach on the nuclear issue than President Ahmadinejad.

"Under Khatemi's government (the strategy was) let's not get sanctioned, let's not get isolated, even if that means our nuclear program advances very slowly or not at all," Katzman says. "Now it's completely changed.  Basically, the strategy of Iran now is, we want our nuclear program to make progress.  And hopefully we will avoid major penalties, we will try to avoid major penalties.  But the primary goal is to make progress on the technology right now and not have the program frozen.  And it is a distinct difference since Ahmadinejad took power."

There is broad consensus in the international community that Iran is pursuing nuclear weapons.  Iran denies this and says it is only asserting its right to peaceful nuclear energy. 

The United States also took a new approach when it offered to join the European talks with Iran on the issue, but only if Tehran first freezes its uranium enrichment, which it recently resumed.  Iran says it will not accept any preconditions for talks.  However, analysts say there is still enough ambiguity in Iran's response that talks cannot yet be ruled out.

Hooshang Amirahmadi says President Ahmadinejad is taking a big gamble in pushing for his strategy on the nuclear issue.

"If Ahmadinejad was to fail in this process of negotiation with the U.S., he will pay for it dearly, actually, in the very worst way," Amirahmadi says. "But if he succeeds in this process, then he will obviously become known as someone who changed Iran's history, in a way."

The Bush Administration has said it is keeping all options open, which includes the possibility of military action against Iran.  While any such action is still seen a long ways off, Ken Katzman says the Iranian leadership is thinking about such a possibility, however unlikely.

"Iran is not necessarily as scared of a U.S. strike on its nuclear facilities, as I believe it is scared of a U.S. strike on its conventional capability," Katzman says. "If the U.S. were to strike its conventional capabilities and render it no longer a Gulf power, a Caspian power, Iran would really be in many ways defenseless and not a power at all, whether it had a nuclear weapon or not.  And I think that this is what Iran is really nervous about."

If Iran is indeed seeking a nuclear weapons capability, estimates vary on when it might achieve that goal, ranging from as low as four years, as U.S. Director of National Intelligence John Negroponte said recently, to as high as 10 years.