– The Iranian nuclear talks are playing out in classic fashion: A self-imposed deadline appears to have been extended due to disputes, with the sides publicly sticking to positions and facing internal pressure from opponents ready to pounce on any compromise. Should the talks actually collapse, the alternatives are not appealing. Here are some scenarios and questions to consider:

IS WAR an OPTION?

The Obama administration continues to say it has the option of using military force to stop Iran from getting a nuclear weapon, should diplomacy fail. It does not provide details publicly, but military officials acknowledge that the most likely form of U.S. attack would be aerial bombing of Iranian nuclear facilities, some of which are deep underground. Iran has a substantial air defense system. But Obama says U.S. warplanes could still penetrate Iranian airspace. Still, senior Pentagon leaders have publicly stressed the limitations of bombing, saying it likely would delay Iran's development of a bomb by no more than three years while strengthening its inclination to covertly go nuclear.

more sanctions?

It seems the world is not prepared to truly bring Iran to its knees by shutting off the flow of capital and goods. That would involve an expensive and politically explosive land and sea blockade as well as a militarily enforced no-fly zone across a country 2 ½ times the size of Texas. That leaves tougher sanctions as the only realistic way to pressure Tehran economically. But even that could be a tough sell outside the U.S. The Iranian people who would suffer are largely captive, and some countries, like China, India and Japan, still depend on diminished but still significant exports of Iranian oil.

Is there a DIFFERENT PROCESS available?

After the initial recriminations, both sides are likely to look for ways to salvage the progress made over the past two years in reducing tensions and lowering the chance of a new Mideast war over Iran's nuclear program. Iran may be ready to resume talks if alternatives arise to physical inspection of the non-nuclear sites.

Could Iran QUICKLY DEVELOP A BOMB?

The Iranians are unlikely to go all the way, but could push to reach "threshold" status. Iranian officials insist they do not intend to build a nuclear weapon, and there is a "fatwa," an Islamic ruling, against the very idea by the country's top leader, Ayatollah Ali Khamenei. Yet Tehran's bomb-making ability has grown. With no talks constraining Iran, it is likely to resume enriching uranium, which Tehran froze early last year. Iran is years away from the expertise needed not only to develop a working warhead but to be able to mount it on a powerful enough missile.

WHAT WOULD HAPPEN If Iran had a bomb?

If Iran — which is emerging as the top Shiite power in the Middle East — does become a threshold nuclear weapons state, a domino effect seems likely. Sunni Saudi Arabia — with the oil wealth to buy much of the nuclear prowess that Iran has labored to produce — has hinted it would feel compelled to acquire the same status. Egypt could also follow suit.

Associated Press