What will Iran do with the big “signing bonus” – perhaps as much as $150 billion – coming its way thanks to the nuclear pact negotiated by the Obama administration?

The current debate revolves around how much the regime will spend on its suffering citizenry – National Security Adviser Susan Rice asserts that “for the most part” the windfall will be spent on “the Iranian people and their economy” – and how much on “bad behavior in the region” of the sort the world has come to know so well: support for the Assad regime, Hezbollah in Lebanon, Shiites in Iraq and around the Gulf, its proxies in Afghanistan, and terrorist operations.  And it’s a good bet that, when Tehran decides finally to go nuclear, it will be a short sprint for which they will have been prepared well.

But these all anticipate that Iran will behave in the future as it has in the recent past, and this is a very uncertain bet.  What is perhaps more indicative is Iran’s rush to conclude a deal and take delivery – without waiting for the conventional arms sanctions to expire and also without a peep of protest from the White House or the West – of the Russian S-300 air defense system.  The prospects are more than fair-to-middling that the mullahs will follow China’s “anti-access” and “area-denial” path, purchasing a bigger fleet of increasingly accurate short-range ballistic and cruise missiles (also quite capable of carrying small nuclear warheads), submarines and sensors and the other elements of Chinese military modernization program that have put the Pentagon into a tizzy.  For $150 billion, Iran could probably buy the People’s Liberation Army’s Second Artillery – which controls China’s “strategic” rocket force – several times over.  Iran’s goal, as China’s has been, will be to raise the conventional cost of U.S. and allied operations in the region, holding local airfields, command centers, surface combatants and, particularly, aircraft carriers, increasingly at risk.  It seems quite likely that Beijing would be more than pleased to cozy up to Tehran by offering bargain basement prices on both ready systems, technology transfer and operational expertise.  And adding a Persian bead to its “string of pearls” around the Indian Ocean will be tempting to the Chinese.

There are two related points to ponder if Iran takes the China path.  One is military: a future American president will not “have the same options” militarily that Obama or George Bush had.  Nor will Israel.  The cost of a conventional strike to cripple Iran’s nuclear program, or simply to respond to other forms of “bad behavior” is about to skyrocket.  And with hundreds of billions to blow on selected military modernization, the Iranians will be improving their position rapidly; thanks to the constraints of the Budget Control Act, the U.S. military will not.

The second point is geopolitical: past Iranian performance is no guarantee of future behavior.  Iranian revolutionaries and Persian nationalists agree that their country is the natural hegemon of the region and should be among the world’s most influential powers.  Iranians have had to suffer for their ambitions since 1979 and feel – thanks to Barack Obama, quite reasonably – that they stand on the threshold or reclaiming the glory they are due.  The idea that Tehran will continue to creep around quietly, relying only on “soft power,” indirect means, proxies and terrorists, sounds more like a hope than a hard-headed analysis.  If “Iran Unchained” sounds like a horror movie…well, it should.