On the face of it, the decision by the Arab monarchies of the Persian Gulf to establish a joint military command indicates the six member states of the Gulf Cooperation Council are seeking to bolster their collective security against Iran amid signs of a rapprochement between their regional rival and the U.S.-led Western powers.

The leaders of those states -- Saudi Arabia, the United Arab Emirates, Kuwait, Qatar, Oman and Bahrain -- announced the move at the end of their annual summit in Kuwait City Wednesday, without providing any details of how that might be achieved.

But they've been saying the same thing at these summits for the last decade -- and done little.

With the Middle East convulsed by political and religious upheaval and facing potentially major shifts in the geopolitical realities, the Kuwait summit's decision could signal a long-delayed effort by these increasingly embattled monarchies to coordinate their defense systems against common threats.

Yet in military terms, the GCC alliance remains a cluster of separate defense establishments with little meaningful coordination on collective security.

The most that can be said is they are, to one degree or another, all buying pretty much the same weapons systems, mainly from the United States, Britain and France. But inter-operability among the six states is poor despite joint training exercises.

The Americans have been pressing the GCC states to develop a gulf-wide defense policy that would include a collective strategy, joint procurement, training and tying together their early warning and missile defense systems.

The bottom line has been that Saudi Arabia and its partners have relied on U.S. protection, primarily from Iran, in return for which they buy billions of dollars worth of advanced weaponry and hire thousands of Western technicians to maintain them because they have been incapable of doing it themselves.

That seems to work out for all concerned, but with the United States slashing its defense budget and reducing its military presence in the oil-rich gulf, which began 40 years ago to protect the strategic region from Soviet encroachment and later against an Islamist Iran, conditions are changing.

The Nov. 24 interim nuclear agreement between Iran, under reformist President Hassan Rouhani, and the United States and its European allies, has heightened concerns in the GCC the Americans are disengaging and new security paradigms are urgently required.

U.S. Defense Secretary Chuck Hagel sought to reassure the GCC of the U.S. strategic commitment by opening the door to the sale of more advanced weaponry during a regional security meeting in Bahrain Saturday.

But he stressed the gulf powers should acquire these collectively, rather than separately as they do now. The United States, he said, would place "even more emphasis on building the capacity of our partners in order to complement our string military presence in the region."

The main obstruction to meaningful unified action by the members of the GCC, established in 1981 amid the 1980-88 Iran-Iraq war in which the monarchies supported Arab Iraq against Persian Iran, has been deep-rooted dynastic rivalries between the ruling families.

This stemmed to a large part to Saudi Arabia's dominance of the alliance, and the reluctance of the smaller monarchies to put their armed forces under Saudi command.

"Divergent state interests" will continue to impede GCC steps toward unity," observed David Weinberg, senior fellow at the Foundation for Defense of Democracies.

"Oman and Qatar will likely resist making military consolidation binding in the future for fear of putting their marine natural gas fields at risk."

The new Iranian administration has been offering more cordial relations with the GCC leaderships since the Nov. 24 agreement in Geneva.

But the 32-month-old civil war in Syria where Iran and its Shiite proxies are aiding the embattled regime of President Bashar Assad, a key Iranian ally, remains a major obstacle. Saudi Arabia, in particular, wants Assad toppled.

The GCC states remain deeply suspicious of Tehran. Oman, which played a key backchannel role in the secret diplomacy that led to the Nov. 24 agreement, declared Sunday it will not participate in a Saudi-proposed plan to upgrade the GCC to a political union.

Closer political links have been on the agenda since the Arab Spring upheavals of 2011 that toppled three Arab dictators, and shook the gulf monarchies to the core.