After 20 months of negotiations, the Obama administration last week reached agreement with Iran, China, France, Russia, the UK and Germany on a 15-year accord to “normalize” Iran’s civil nuclear program. Should this agreement survive the opposition of sections of the US ruling elite, it will constitute a significant tactical shift on the part of US imperialism, one with potentially far-reaching implications.

Since the 1979 Iranian revolution toppled the Shah’s bloody US-backed dictatorship, implacable opposition to Iran has been a constant in US foreign policy. During the past 12 years, Washington dramatically intensified its campaign of bullying and threats. Having ordered the invasion of Afghanistan and Iraq, respectively Iran’s eastern and western neighbors, George W. Bush twice came close to launching war against Iran.

In 2009, the Obama administration sought to bring about regime-change in Tehran via a “Green Revolution” fomented through unsubstantiated claims of a stolen election. Two years later, Washington cajoled its European allies to join the US in imposing the most punishing economic sanctions ever deployed outside a war.

Now, in exchange for sweeping concessions from Iran, Washington has agreed to suspend the economic sanctions and provide Tehran a 15-year path to “normalize” its civil nuclear program.

Obama has stipulated that last week’s agreement with Tehran is limited to the constraints on its civil nuclear program. Yet Obama, Secretary of State John Kerry and other leading US officials have also made clear that they view the agreement as exploratory, a means to test Iran’s intentions. Their policy of “engagement” with Iran is a strategic bet that through a combination of continuing pressure and inducements, including an influx of Western investment, US imperialism will be able to harness Tehran to its predatory agenda.

The Republican Party leadership, the Wall Street Journal and the American Israel Public Affairs Committee (AIPAC) are publicly opposing this shift. They are demanding that Obama extract iron-clad guarantees of Tehran’s submission and warning against sidelining the US’s traditional Mideast client states, above all Israel and Saudi Arabia.

The public bluster of the Republicans, however, is not necessarily an indication of the real intentions of the main decision-makers in the Republican Party. To some extent, the Republicans’ opposition can prove useful to Obama in prying further concessions from Tehran. That said, it is far from certain the Iran nuclear accord will be implemented, let alone endure.

The nuclear accord and the fractious ruling class debate over it are a reflection of the mounting problems that US imperialism faces as it seeks through aggression and war to offset the erosion of its relative economic power and to confront multiplying challenges to its global hegemony.

There is deep dissatisfaction within the US ruling class over the outcome of the three major wars the US has waged in the broader Middle East over the past decade-and-a-half. In Ukraine, Washington has thus far been stymied, with the sanctions imposed on Russia failing to produce the desired results. To the Obama administration’s dismay, many of its closest allies, led by Britain, defied the US and signed up as founding members of the Chinese-led Asian Infrastructure Development Bank earlier this year.

All of this has left the Obama administration and the US ruling class groping for an effective, integrated plan of attack.

Certain things can be said concerning the trajectory of US imperialism, the strategic calculations that underlie the proposed shift in US relations with Iran, and the implications of this shift:

* Obama and the entire US ruling elite are determined to maintain US global hegemony through military force.

There is something decidedly ominous about the president’s repeated proclamations over the past week that the failure of his diplomatic turn to Iran would result in war. These comments underscore that Washington is far from renouncing violence and point to the explosive character of global relations.

* Central to American imperialism’s global strategy is dominance over Eurasia, the vast land mass that is home to almost two-thirds of the world’s population.

In pursuit of this aim, Washington has long viewed Iran as an especially significant prize. The country stands at the intersection of three continents (Europe, Asia and Africa), commands the Straits of Hormuz, through which 40 percent of the world’s exported oil flows, straddles two of the world’s most energy-rich regions (Central Asia and the Middle East), and itself possesses the world’s second largest natural gas and fourth largest oil reserves.

* Washington’s trumped-up conflict with Iran over its nuclear program was never just about Iranian-US relations. Nor was it solely about control of the Middle East. It always involved the broader question of US relations with the world’s major powers.

Even as US dependence on Mideast oil has declined, Washington has stepped up its efforts to maintain control over the Middle East so as to ensure domination over a region that supplies many of its principal competitors in Europe and Asia, including China and Japan, with much of their oil.

* When Obama claims, as he has repeatedly done, that for US imperialism war is the only alternative to a nuclear deal with Iran that realizes many but not all of Washington’s objectives, he is, for once, not lying.

Had the sanctions regime started to unravel, Washington would have faced a demonstrable challenge to its pretensions to world leadership, one that it could not walk away from without suffering a major geo-political defeat. In response, it would have been obliged to extend the sanctions—in other words, retaliate against the “sanctions-busters” by freezing their overseas assets and denying Iran access to the US-European controlled world banking system. Or, in order to avoid such action, which could quickly spiral into a military confrontation with China or Russia, the US would have been compelled to render the issue moot by abandoning the sanctions in favor of all-out war.

The Pentagon has long been planning and gaming such a war. And while the American people know nothing of these plans, in various think tank reports it is openly admitted that a war with Iran—a country four times the size of Iraq and with nearly three times the population, and which has significant state and foreign militia allies—would quickly envelop the entire Middle East. It would further inflame the US-stoked Sunni-Shia sectarian conflict and, at the very least, tie down much of the US military for a protracted period. Last, but not least, such a war would incite rising popular opposition in the US, where class tensions are already fraught after decades of social reaction.

Obama is arguing that US imperialism has a cheaper, more prudent alternative. One, moreover, that, as Defence Secretary Ashton Carter boasted Sunday, “does nothing to prevent the military option” in the future.

* The agreement with Iran has been designed to give the US the maximum leverage over Iran and the maximum strategic flexibility. Should Tehran prove insufficiently pliant or should circumstances change, the US can initiate procedures to automatically “snap back” the sanctions and pivot back to confrontation with Iran.

Moreover, all of Obama’s arguments in favor of the nuclear accord—his assertion that it is better to “test” Iran’s intentions than immediately embark on a war that could prove hugely damaging to US imperialism’s strategic interests—are predicated on Washington’s supposed right to wage pre-emptive war against Iran.

* The Obama administration sees Western engagement with Iran as a means of preventing Tehran from being drawn into closer partnership with China and Russia. China is already Iran’s biggest trading partner and Russia its most important military-strategic partner.

A further US priority is to see if it can enlist Iranian support in stabilizing the Middle East under Washington’s leadership. The US and Iran are already at least tacitly allied in supporting the Iraqi government and Iraqi Kurdish militia in opposing ISIS in Iraq.

The Obama administration has also served notice that it intends to use the nuclear agreement to pressure Iran to assist it in reaching a political agreement in Syria that would see Bashar al-Assad’s Baathist regime replaced by one more amenable to US interests. Reversing previous US policy, Obama announced last week that Tehran should “be part of the conversation” in resolving the Syrian conflict.

* Longer term, the supporters of Obama’s Iran gambit aim to “turn” Iran, transforming it into an advance post of US imperialism in the Middle East and all Eurasia. That means to return the country to the type of neo-colonial subjugation that existed under the Shah’s regime.

Toward this end, Washington plans to probe and exploit the deep fissures within Iran’s bourgeois-clerical regime. It is keenly aware that the reins of Iran’s government are now in the hands of a faction (led by ex-president Hashemi Rafsanjani and his protégé, the current president, Hassan Rouhani) that has argued since at least 1989 for a rapprochement with Washington and has longstanding close ties to European capital.

* The Iran nuclear accord only intensifies the contradictions in US foreign policy, laying the basis for future shocks.

While exploring engagement with Iran, Washington is seeking to placate its traditional regional allies by showering them with offers of new weapons systems and increased military and intelligence cooperation. These actions threaten Tehran, which—notwithstanding the relentless US media campaign aimed at depicting it as an aggressor—already faces a massive military technology gap, not just with Israel, but with Saudi Arabia and its Gulf allies.

Nor can the US afford to stand idly by as the European powers scramble to get back into Iran. On Sunday, Germany’s Vice-Chancellor and SPD leader Sigmar Gabriel arrived in Iran at the head of a German business delegation. French Foreign Minister Laurent Fabius has said he will soon follow.

To secure support from the US ruling elite, Obama is stressing that he has only agreed to lift the latest round of US sanctions on Iran. Other sanctions imposed in the name of opposing terrorism remain, meaning US corporations continue to be effectively barred from doing business in Iran.

If the US is not to lose out in the race to secure Iranian assets, it must either move forward with rapprochement—over the strenuous opposition of Washington’s current Mideast allies—or revert back to confrontation and demand the Europeans and others follow suit.

* Other strategic calculations, many of a pragmatic and short-term character, also appear to be bound up with the Obama administration’s decision to consummate a deal with Iran now. One cannot make firm judgments about these calculations, as events are moving rapidly and Washington’s policies are fraught with contradictions.

However, it was striking that in the lengthy interview Obama gave to the New York Times last week, the US president praised President Vladimir Putin, saying the agreement with Tehran could not have been reached without Russia’s strong support. He added that he had been “encouraged” by a recent phone call Putin made to talk about Syria. “That,” declared Obama, “offers us an opportunity to have a serious conversation with them.”

Is it possible that Obama is considering responding positively to Putin’s pleas for a ratcheting down of tensions over Ukraine in exchange for Moscow’s abandonment of Syria’s Assad? Could this be bound up not just with the crisis of US policy in the Middle East, but also with growing tensions between Washington and Berlin? Could this be intended as a shot-across-the-bow to Germany?

The US ruling elite has reacted with dismay to Germany’s cavalier role in the recent negotiations between the EU and Greece—not out of any concern for the Greek masses, but because of Berlin’s bald assertion of its new role as Europe’s disciplinarian.

Should the US ruling elite ultimately opt to move forward with the Iran deal, it will be from the standpoint of better positioning itself to withstand challenges to its dominance, including through military means, from its more formidable opponents, not only Russia and China, but also Germany, Japan and the other imperialist powers.