How does Barack Obama sleep at night? The number of crucial issues urgently awaiting his attention grows by the day. And if he has time to pick up a magazine, turn on the radio or read a book, he could drown in volunteered advice about troubles he might not have even considered yet. Sadly, some problems do need immediate attention, and delay could prove disastrous. Obama knows that.

One situation facing the entire planet, but staring sharply into Israel’s eyes, is the ticking time bomb of Iran’s nuclear program.

The election of Obama, who brings a completely different approach to this and other problems, has brought a sense of “Now it will be OK” to that tough quandary. During the campaign, Obama famously declared he would engage in direct talks without preconditions with Iran’s leaders. What he did not spell out was what exactly the United States would say to Iran during those talks in order to produce results.

After all, European representatives spent half a decade holding direct talks without preconditions with Iran’s leaders. What the world gained from those efforts was the knowledge that Iran is brilliant at talking in circles. Gallons of tea and coffee and kilos of cookies and pistachios were consumed by smooth Iranian and European diplomats while scientists nearby pushed ahead with Iran’s uranium enrichment in Natanz and construction of a nuclear reactor at Bushehr.

Iran’s thousands of centrifuges are spinning at this very moment, adding to a stockpile estimated at more than 650 pounds of enriched uranium.

Even if Iran’s deliberately transparent threats to destroy Israel prove untrue, there are many reasons to worry. The prospect of nuclear weapons in the hands of a regime whose constitution calls for spreading revolution has sent chills across the region. Proliferation experts say that if Iran is allowed to build a nuclear weapon, a torrent of nuclear programs will cascade across the region. Before long, unstable countries with weak governments will struggle to guard their own nuclear stocks.

Already, poor nations such as Egypt and Jordan have announced plans to get into the business. Other predominantly Sunni regimes are doing the same, worried about Shiite Iran’s political ambitions. And Iran’s practice of arming and training militant groups such as Hezbollah in Lebanon and Hamas in the Palestinian territories conjures even more troubling scenarios.

The Iran nuclear crisis started in 2002, when exiles revealed that the Islamic Republic had engaged in a secret nuclear program in violation of its international treaty commitments. For a while Tehran lied. Eventually, the facts became undeniable and Iran acknowledged its nuclear research activities, but insisted it aspired only to develop electricity, not bombs.

More than six years later, after countless U.N. resolutions and sanctions, Iran proudly boasts of its thriving nuclear activities and defiantly vows they will never stop.

Obama’s plan to talk with Iran is not wrong. But talks alone guarantee nothing. Diplomacy will work if emissaries come bearing potent words. The time is propitious for a new message. That’s because Iran’s economy stands on the verge of collapse. With oil prices down by more than 70 percent, the Islamic republic’s balance sheet looks worse than General Motors’. And there’s no bailout in sight. Iranians feel betrayed by President Mahmoud Ahmadinejad, who came to power vowing to improve living standards, and accomplished the opposite.

Soon-to-be President Obama comes to power loaded with international good will, in sharp contrast with his predecessor. If Obama can assemble a more determined international coalition to face Iran with watertight economic sanctions, and if he publicly tells the Iranian people what exactly their government is making them pay for the sake of the nuclear program, Iran may just have to fold. That’s what every government in the Middle East — from Saudi Arabia to Israel, from Morocco to Iraq — hopes will occur.

The big question is what will happen if Iran stands firm and refuses to back down. Like every difficult problem, the choices are not good. Obama has already said that allowing Iran to build nuclear weapons is not an option. What he will do if diplomacy fails is the kind of question that keeps presidents awake at night.