With each report from the United Nations nuclear agency, the choices the world faces regarding Iran’s nuclear program become more stark.

The most recent one essentially confirmed that Iran is pursuing nuclear weapons. The International Atomic Energy Agency, not known for using alarmist tones, describes Tehran’s activities developing nuclear triggers for atomic weapons, advanced research on warheads that can be delivered by medium range missiles, computer modeling of nuclear explosions, and other efforts that have nothing to do with producing nuclear energy. Then again, who actually believed Iran’s claims — still continuing — that this is all about producing electricity?

So, now what?

A nuclear Iran would transform the Middle East. It would spark an arms race, with Saudi Arabia, Turkey, Egypt and the United Arab Emirates all likely to build atomic weapons. Given the instability of the region, one can only imagine the danger of introducing large quantities of nuclear materials, let alone weapons there. It would make Iran’s repressive, anti-Western agenda more politically influential than ever. And that’s if doesn’t use the weapons.

All discussions about Iran happen with an eye towards Israel. After all, Iran has spent decades arming the groups that regularly attack Israel. Iran has never called for peace between Israelis and Palestinians, but has worked hand in glove with groups opposed to peace and to Israel’s existence. It has never been shy about saying what it would like to see happen to the “Zionist entity.”

Given the rhetoric from Iran, and the responses it has elicited in Israel, the fear in many corners is not just what Iran would do to Israel, but what Israel might do pre-emptively to Iran.

The most intense of all the discussions on the subject rages in Israel itself.

Some leading Israeli security experts argue it would be catastrophic for Israel to attack Iran. Others say it would be suicidal not to. The former maintain that an Israeli attack would bring about the very disaster Israel fears from a nuclear Iran. Others say a nuclear-armed Islamic Republic would change the face of the Middle East. It would sideline anyone who wants to make peace, fortifying those who say Israel should be destroyed. Iran might share nuclear materials with terrorists, or it would protect them with its implicit nuclear threat. Ultimately, a nuclear Iran could either destroy Israel, or make its tiny territory unlivable after just one detonation. At times the discussion sounds like choosing between two forms of annihilation, the kind of dilemma no other country faces.

Israel faces incalculable losses if it attacks Iran, or if Iran ends up succeeding in its quest for nuclear weapons. Even if NATO decided to launch the fight, Israel would likely become a target of Iran and its allies, Hezbollah, Hamas, and perhaps volunteers from other places.

That’s why Israeli leaders have urged the international community, not to bomb Iran, but to impose “crippling” sanctions that will persuade it to change course.

But this is not just about Israel.

A few days ago, Jeffrey Goldberg of the Atlantic Monthly argued that President Obama may make the decision to take out Iran’s nuclear installations, saying Obama has powerful reasons for wanting to put an end to the controversial atomic program. And he wasn’t talking about wanting to win the next election.

Allowing Tehran to win this contest over nuclear weapons, Goldberg wrote, would mark a major defeat for the U.S. in a three-decades-old battle over influence in the Middle East

Goldberg also reminds us that Obama, even before he became president, had a profound commitment to a world without nuclear weapons. If Iran is not stopped, Obama would suffer “a bitter defeat,” becoming the president who allowed “the greatest expansion of the nuclear arms club in recent history.”

An American operation, argues Goldberg, would enjoy strong support from Washington’s allies in the region, Israel, Turkey, and the nations of the Gulf — Saudi Arabia, Kuwait, Bahrain, and the UAE.

Then, unavoidably, there is Israel. Goldberg says Obama doesn’t want to be the president that is remembered for failing to guarantee Israel’s survival.

Soon after the IAEA report was released, Iranian President Mahmoud Ahmadinejad declared Tehran would not move back the nuclear program “even a needle’s width.” The deputy chief of Iran’s armed forces, Brig. Gen. Masoud Jazayeri warned that “we will witness Israel being wiped off the map,” if anyone attacks.

No reasonable person hopes for a war. The only good outcome can come if sanctions, this time including committed participation from China, exert the pressure needed to bring a change of course in Tehran. It’s a long shot, and the clock is running out.

• Ghitis writes about global affairs for The Miami Herald.