Iran's nuclear ambitions predate the clerical dictatorship that overthrew the monarchy in 1979. The late last monarch, Mohammad Reza Shah Pahlavi, reached the same conclusion when Britain, in 1968, suddenly relinquished all of its geopolitical responsibilities east of Suez -- from Singapore to the Suez Canal, including the Persian Gulf and the oil that then fueled most of the Western world.

Throughout the post-World War II era, Pax Britannica in the gulf was costing the British government $40 million a year.

The Nixon Doctrine stepped into the vacuum left by London's decision. This, in turn, led to the anointment of the shah as the guardian of the Persian Gulf that bore the name of Iran's worldly past.

At its height in 500 B.C., the Persian Empire had conquered Asia as far as the Indus River to the east and Greece and North Africa (including Egypt and Libya) to the west. Delusions of grandeur came easily to the shah and then to his turn-the-clock-back theocratic successors.

In 1972, the shah predicted to this reporter that one day Iran would be a full-fledged nuclear power, anointed by the Nixon Doctrine to keep the Soviet Union and its friend Saddam Hussein of Iraq from troublemaking in the Persian Gulf.

The shah explained that his armed forces had to be able to react in half a day to counteract any attempt by the Soviet bloc and its friends to stage a coup in any of the then disunited sheikdoms and emirates. This led to Iran's purchase of Boeing 747s and huge hovercraft as troop carriers.

In retrospect, it doesn't take an overwhelming effort of imagination to see how Iran's superannuated ayatollahs would spare no effort to get their hands on the ultimate weapon.

In 1987, Pakistan and Iran signed a secret agreement on "peaceful nuclear cooperation," which was the cover for Iranian scientists to be given centrifuge training in Pakistan.

In 1992, Pakistan began missile cooperation with North Korea - in return for nuclear weapons knowhow. This led to Pakistan's Ghauri missile, a copy of North Korea's Nodong design.

Among the cognoscenti, there was never any doubt that Iran's constantly denied objective is to achieve nuclear weapons capability. Five of the world's nine nuclear powers are in Iran's geopolitical vicinity -- Russia to the north, Israel to the west, Pakistan and India to the east and the U.S. Navy 5th Fleet (with tactical nuclear weapons) to the south.

Many in Israel concluded that the Jewish state would be the ayatollahs' principal objective. But unless Iran's decision makers have taken leave of their critical faculties, they know Israel could incinerate their domain back to the Stone Age.

There are those in Israel's governing circles who advocate pre-emption. Three of Israel's recently retired intelligence chiefs, including Mossad, Shin Bet and military intelligence, have publicly voiced angry dissent.

They echo what three former U.S. Central Command commanders -- Gen. Anthony Zinni, Gen. John Abizaid and Adm. William J. Fallon-- have said on the record in recent years, namely that bombing Iran's nuclear facilities would be a grave geopolitical mistake.

Gen. David Petraeus, now the CIA director, also had serious reservations when he was CENTCOM commander (2008-10).

Firstly, Iran has had several years notice to dig deep for its most sensitive nuclear operations. Secondly, Israel's fighter bombers barely have the range to reach one or several of Iran's nuclear installations and air-to-air refueling would have to take place over Turkey, Jordan, Iraq or Saudi Arabia.

What former CENTCOM commanders and Israeli intelligence chiefs have in common is intimate knowledge of Iran's formidable asymmetrical retaliatory capabilities. One bomb on Iran and oil prices could shoot up to $300 or even $500 a barrel. Iran's Fifth Column operatives (a 1936-39 Spanish civil war term to explain forces that clandestinely undermine a populace from within to aid an external enemy) are dotted up and down the entire gulf.

Bahrain, U.S. 5th Fleet headquarters in the Persian Gulf and the scene of yearlong clashes between a minority Sunni royal family and a majority Shiite population that includes thousands of pro-Iranian poor.

The Strait of Hormuz, between Oman and Iran, is the world's most important oil chokepoint with a daily oil flow of 16 million barrels, roughly 33 percent of all seaborne traded oil, or 17 percent of oil traded worldwide.

On average 13 crude oil supertankers (averaging 150,000 tons) per day pass eastbound through the strait to Asian markets (75 percent) in India, Japan, China and South Korea. Hormuz channels are 2 miles wide in either direction separated by a 2-mile buffer zone.

Iran would be cutting off its nose to spite its face by sinking a tanker in the Hormuz channels. But al-Qaida and its affiliates would have no such qualms. Coming alongside a supertanker at night in a rubber zodiac outboard and planting a couple of limpet mines on the waterline is no great feat for seaborne terrorists.

Under prodding from Tehran, Hezbollah in Lebanon and Hamas in Gaza are known to have discussed a joint one/two punch in the event of an Israeli nuclear attack.

Israel's policy-makers argue they cannot allow Israel to absorb a nuclear weapons attack and respond with a nuclear second strike. Tens of thousands of Israelis would be killed and a city destroyed before Israel could unleash retaliatory incineration against Iran.

Ron Tira, author of "The Nature of War: Conflicting Paradigms and Israeli Military Effectiveness," says "in the next stage Iran may focus on challenging the Saudi Royal House … (if it fails) the remaining Arab opposition to Iran may disintegrate as well."

An Israeli-Palestinian agreement isn't even a shimmering mirage on the darkening geopolitical horizon. The much ballyhooed Arab Spring and the U.S. withdrawal from Iraq have undermined the balance of power and turned Iran into the dominant player that is now "developing a strategic reach to the Mediterranean," says Tira.

Hence, the renewed danger of an Israeli pre-emptive strike against Iran's nukes.