The strained relationship between Obama and Israeli Prime Minister Benjamin Netanyahu plays a role, as does the rise in influence of conservative political parties in Israel. U.S. officials have concluded that Israel will go its own way on Iran, despite U.S. objections, and may not give the U.S. much notice if it decides to launch a strike, U.S. and other officials said. The officials spoke on condition of anonymity to discuss sensitive diplomacy.
The Obama administration is concerned that Iran's claim this week that it is expanding nuclear operations with more advanced equipment may push Israel closer to a strike.
Obama last month approved new sanctions against Iran that would target its central bank and its ability to sell petroleum abroad.
The U.S. has delayed implementing the sanctions for at least six months, worried about sending the price of oil higher at a time when the global economy is struggling.
A senior commander of the Revolutionary Guard force was recently quoted as saying Tehran's leadership has decided to order the closure of the Strait of Hormuz if the country's petroleum exports are blocked due to sanctions.
Panetta linked the two crises Thursday, saying an Iranian nuclear weapon is one “red line” the U.S. will not allow Iran to cross, and a closure of the strait is another. “We must keep all capabilities ready in the event those lines are crossed,” Panetta told troops in Texas.
He did not elaborate, but the nation's top military officer, Joint Chiefs of Staff Chairman Gen. Martin Dempsey, has said the U.S. would take action to reopen the strategic waterway. That could only mean military action, and there are U.S. warships stationed nearby.
“The United States and the international community have a strong interest in the free flow of commerce and freedom of navigation in all national waterways,” White House press secretary Jay Carney said Friday, adding that Iran is well aware of that position. “Our views are clear, we're expressing them publicly and privately, and I'll leave it at that.”
International talks to barter Iran out of building a nuclear weapon are nearly collapsed, the United States and several partners are on the verge of applying the toughest sanctions yet on Iran's lifeblood oil sector, an increasingly cornered Iranian leadership is lashing out in unpredictable ways and faces additional internal pressures with a parliamentary election approaching.
All that adds up to a new equation, U.S. and western diplomats said. A unilateral U.S. military strike on Iran's nuclear infrastructure remains unlikely but no longer unthinkable, while the likelihood of an Israeli military strike has increased.
Immediate consequences would probably include an unpredictable spike in oil prices, ripple effects in troubled European economies and a setback for the fragile U.S. economic recovery. Longer term, a strike or a full-on war would almost surely ignite anti-American sentiment in the Middle East and beyond and empower hard line political movements in newly democratic Egypt and elsewhere.
Although the Obama administration wants to avoid conflict, it is locked in a cycle of provocation and reaction that feeds Iranian fears and may make war more likely, said Suzanne Maloney, a former State Department Iran expert now at the Brookings Institution.
“The tactics the administration has been taking means conflict becomes more likely, because of the potential for miscalculation and the level of tensions and frustrations on both sides,” she said.