Editor's Note: As Russia helps Iran flip the switch this weekend on its first nuclear reactor, Tehran also takes a giant -- and dreaded -- step closer toward becoming a regional nuclear threat. FoxNews.com examines the military, diplomatic and political options and consequences of trying to stop Mahmoud Ahmadinejad's nuclear ambitions.
TOMORROW: Political and Diplomacy
As Iran, with Russia's help, gets ready to flip the switch on its first nuclear power plant, Washington is engaged in a frenzied debate over whether Israel should consider launching an air attack designed to cripple Tehran's nuclear capabilities.
But key military officials and analysts say Iran has already passed the point where a strike would deal its entire nuclear program a fatal blow. The country might be persuaded to abandon any efforts to build a bomb, they say, but -- like it or not -- Iran is going nuclear. And no number of Israeli F-16s is going to change that.
"We can't stop it. We can slow it down," Rep. Adam Smith, D-Wash., a member of the House Armed Services and Intelligence committees, told FoxNews.com.
The mechanics of shutting down Iran's nuclear program are mindboggling. The Bushehr facility -- a station along the Persian Gulf that uses non-weapons-grade fissile material -- will be Iran's first functioning nuclear plant; engineers began loading its Russian-provided fuel on Saturday.
But Bushehr is just one piece of a much larger puzzle.
Iran has a uranium-enrichment plant at Natanz and another at Qom, which Western allies blew the whistle on last year. Several facilities critical to the nuclear program are known to be scattered throughout the country, and others are believed to exist in unknown locations. Iran has committed to building more reactors and more enrichment facilities, and as long as it has nuclear physicists, the regime can continue to pursue its goals.
Attacking Iran's nuclear program might be like Mickey Mouse chopping broomsticks in The Sorcerer's Apprentice. The program could be taken down -- but for how long?
Smith, in urging caution toward the idea of a military strike, was echoing Defense Secretary Robert Gates, who said last year that an attack could buy time, but it would not halt the program.
But that doesn't mean a strike is off the table, from either the United States or Israel. Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, stated plainly in an interview on Aug. 1 that the U.S. military has an attack plan for Iran.
Richard Russell, who served 17 years as an analyst with the CIA and now teaches at National Defense University's Near East and South Asia Center for Strategic Studies, described the "credible threat" of a strike as potentially more potent than a strike itself.
Right now, Russell said, the Iranians see the United States as bluffing, as they have since the Bush administration -- which puts pressure on Israel. The credible threat of a military strike, he said, helps prevent a peaceful energy program from turning into a weapons factory. That, and sanctions, which have already been imposed by the United States, United Nations and European Union.
For now, the United States and Israel may still have time on their side. Iran needs to cross several hurdles before its nuclear program becomes a blatant international security threat, presuming the country does not comply with the kind of oversight on its current program that would satisfy the United States. It needs the fissile material, either from highly-enriched uranium or plutonium; it needs an actual bomb; and it needs a delivery system to carry it. U.S. officials have said over the past several months that Iran could have enough bomb-making material in a year and a weapon within two years. Estimates about Iran's intercontinental missile capability have varied widely.
The Iranians also need to want to do it. Smith said, based on intelligence he's seen and is free to talk about, the highest levels of the Iranian regime are "conflicted" about whether to cross the line and build a bomb.
Russell said it's not too late, and that a combination of economic sanctions and military threats can persuade Iran to back off from developing a weapon. Smith, too, expressed hope that sanctions will compel Iran to keep its nuclear program peaceful.
But others say there's little doubt that Iran's nuclear energy will soon go beyond feeding the country's electric grid. They wonder whether Iran is closer to a weapon than the West thinks, and they suggest drastic action may have to be taken to ensure the Iranians don't get the bomb, even if it doesn't halt the nuclear program.
"I personally think it will take the use of force against at least elements of the Iranian nuclear program to make this Iranian leadership think it's too costly to continue on this path," said Kori Schake, an associate professor at the U.S. Military Academy at West Point and a former member of the National Security Council staff during the Bush administration.
She said the most credible estimate she's seen is that it would take five years for Iran to produce a deliverable nuclear weapon from the time Tehran decides to do so.
"We don't know if they've chosen to do it. I personally believe they chose to do it a few years ago, and so the clock's ticking," she said.
John Bolton, U.S. ambassador to the United Nations during the Bush administration, said it's "only a matter of time" before the Bushehr plant creates the plutonium needed to pave the way for weapons production. He's expressed concern that unless Israel strikes Bushehr before fuel is loaded, the radiation from an attack would render that possibility remote.
The scenarios for an Iranian backlash and turmoil in the broader Middle East in the wake of a military strike are ghastly -- the specter of a new conflict comes as the last U.S. combat brigade in Iraq begins to pull out. And those scenarios are the basis for the extreme caution with which U.S. officials talk about a military option.
"Nobody knows how bad it could get," said Steven Simon, a former director with the National Security Council and senior fellow with the Council on Foreign Relations.
Simon suggested the Israelis, who have previously knocked out reactors in Iraq and Syria before they went active, have greater reason to attack than the Americans. But he agreed that military action only delays, and doesn't stop, nuclear development -- including a nuclear weapon.
"They keep plugging away at it. They'll come up with something," Simon said.