Nothing new under the desert sun in Iran. The Islamist leadership is starting out 2012 with its usual jagged chin forward:

• Iranian leaders, in the face of enhanced economic sanctions, have threatened to illegally block the Strait of Hormuz (through which one-sixth of the world’s oil flows) and have suggested American vessels aren’t welcome in the Persian Gulf.

• Uranium enrichment continues for Iran’s so-called “peaceful” nuclear program, which despite the nation’s true intentions (of which we can be reasonably assured), is violative of the conditions imposed by the International Atomic Energy Agency (IAEA) and by most Western nations.

• On the heels of a successful United States Navy action to rescue Iranian fishermen from Somali pirates, the Iranian Fars news agency, close to the Revolutionary Guard forces, suggested the Americans were just dramatizing a routine event (though the official government release at least “welcomed” the U.S. intervention).

• Iran just imposed the death penalty on a former U.S. serviceman of Iranian descent accused of spying for the Central Intelligence Agency while in Iran.

The world is not amused by the building intransigence of Iran, but the question is, what is the world going to do about it? And in the absence of the world’s action, what will Israel do about it?

It’s one thing for Iran to saber-rattle toward America and Israel, it’s quite another for it to continue its quest for nuclear weaponry (something other Middle Eastern Arab nations are not altogether pleased about) and to threaten to block oil transports. So the world is starting to push harder.

The current American sanctions cut off those who do business with Iran’s Central Bank from U.S. financial markets. The European Union is expected to come on board soon. But China, India and Japan accounted for over 50 percent of Iranian oil purchase last year, and it’s by no means clear that those countries will be willing to do anything, despite lobbying by the U.S. In fact, after seeing a drop in demand for Iranian oil, China is said to be using its leverage (as buyer of 20 percent of Iranian oil exports) to push for discounts.

That may well be how Iran keeps the oil money flowing in the short run, but it’s not going to prevent the U.S. and others from fighting back if oil shipping from other nations such as Saudi Arabia (which has indicated it will increase production and distribution) is blocked. Let’s say that Iran does what it has threatened to do in retaliation, cutting access to the Strait and the Gulf. What then?

Well, first, the world, through the International Energy Agency, not to be confused with the IAEA, could decide to open world oil reserves while some nations – presumably with the U.S. Navy at the forefront – fight to preserve open sea lanes for world oil commerce.

This really is not a smart path for Iran at all. Closing shipping lanes would be a true international violation, which would make it far more difficult for powers such as China, Russia, Japan and India to remain on the sidelines. Second, it would give U.S. forces a justification to ramp up their assertiveness, presumably with Europe’s blessing.

And just as critically, Iranian belligerence would pit Iran’s muscle against American and world naval forces at just the wrong time in the development of its nuclear program, which would have at least two consequences. First, it would push world opinion against Iran as a constructive trading partner nation. But it would also give both the U.S. and Israel some political and diplomatic cover to conduct military strikes against key installations within Iran.

Moreover, depending on how the death penalty case plays out – if Amir Mirzaei Hekmati, the accused American, is not truly a spy, but merely a pawn in Iran’s antagonism toward the West – then American sentiment may push political support for an Iran offensive even further into overdrive.

There’s another consideration here, too. Many of the Arab nations, while some won’t say it, aren’t all that enamored of Iran’s aspirations for regional dominance. The threat of nuclear capability in the hands of Iran’s bellicose president and reigning ayatollahs does not sit well with moderate Arab states. So any support Iran would desire in its own backyard will be found wanting.

It’s been assumed to date that the Israel attack scenario was an either-or proposition – i.e., if the world doesn’t proceed against Iran, the Israelis will. But if all the stars begin to align against Iran – on oil, the Persian Gulf, nukes, an American held unlawfully, then the walls that might have prevented unilateral Israeli action to date could begin to crumble. Israel could become simply another nation engaged to beat back the hateful and potentially violent regime of the ayatollahs.