On Friday, just one day after it was awarded a non-permanent, two-year seat on the United Nations Security Council, Saudi Arabia abruptly announced to the world that it was rejecting the seat, much to the bafflement and diplomatic dismay of the rest of the world.

It’s unprecedented for a country to make a years-long effort to win a non-permanent seat, only to turn around a day later to renounce the seat.

The Saudis denounced the Security Council’s inability to act in the Middle East and called for reform:

The manner, the mechanisms of action and double standards existing in the Security Council prevent it from performing its duties and assuming its responsibilities toward preserving international peace and security as required,” the Saudi Foreign Ministry said in a statement. “Allowing the ruling regime in Syria to kill its people and burn them with chemical weapons in front of the entire world and without any deterrent or punishment is clear proof and evidence of the U.N. Security Council’s inability to perform its duties and shoulder its responsibilities.”

Security Council reform is long overdue, but it’s hard to see the Saudis becoming the poster child for political reform in Turtle Bay.

So what gives?

Commentators pointed to several immediate reasons.  The Saudis are angry that US president Barack Obama failed to hold steady in his threat to use military force against Syria.  The Saudis are upset that the United States recently cut off military aid to Egypt’s new, undemocratic government.  The Saudis are worried that the recent steps toward better relations with Iran could mean that the United States places less importance its longtime strategic relationship with Saudi Arabia.

But none of those really give us a full explanation — the Syria showdown was two months ago, and the Saudis would have more influence on the process to rid Syria of chemical weapons from within the Security Council than outside it.  Furthermore, they could use their vote on the Security Council for the next two years as leverage to curry favor with the United States.  And in the ‘P5 + 1’ talks with Iran, Saudi Arabia would certainly have a more central role if it were sitting on the Security Council while Iran struck a deal with the international community.

Eric Voeten, writing at The Monkey Cage, now at home at The Washington Post, argues that Saudi Arabia’s approach to diplomacy has long been a backdoor, behind-the-scenes affair, and that doesn’t fit well with the high profile of sitting on the Security Council:

More important for the case of Saudi Arabia is the responsibility to publicly take positions on highly sensitive political issues. This is the reason that Mexico for a long time didn’t want to serve on the Council: it is one more opportunity to get into trouble with the U.S. The Mexican public often insists that the government take a stance against the U.S. even when the government has pragmatic reasons to to behave differently. Indeed, privately, I have heard from Mexican policy makers (those based in Mexico City rather than in New York) that they experienced their more recent two-year terms as burdens more than privileges.

I strongly suspect this is the reason why Saudi Arabia had never before sought a seat on the Security Council. We all know that the U.S. and Saudi Arabia are strategic allies but this is not because they have converging preferences on most foreign policy issues. Rather, the U.S. needs Saudi Arabia because it has the world’s largest oil reserves and Saudi Arabia needs the U.S. for purposes of defense and to preserve security and stability in the region.

But there may be even deeper reasons for Saudi angst — the decades-long Faustian bargain between the United States and Saudi Arabia may be coming to an end.

The symbiotic relationship between the two countries always depended on a unique set of global political conditions.  The United States needed Saudi Arabia to guarantee access to relatively cheap oil and prevent shocks to the energy market, to remain a staunch anti-Soviet ally during the Cold War, and to support its other geopolitical goals in the Middle East, including the stability of Israel.

Meanwhile, Saudi Arabia welcomed the United States as its top client, depended on the United States to sell it military equipment, enjoyed US efforts to isolate Iran (a longtime Shiite, Persian rival to the Sunni, Arab kingdom) and to push back the Soviet Union’s encroachment on the Arabian peninsula, and, more often than not, the Saudis welcomed the muscular US intrusion into the region to protect Saudi oilfields.  It was a nice bonus that the United States soft-pedaled the Saudi kingdom’s dismal record on democracy, repression, human rights abuses, and women’s rights.

Over the years, top Saudi officials, such as Bandar bin Sultan, the longtime former Saudi ambassador to the United States, formed close ties to top US officials and to both US presidents George H.W. Bush and George W. Bush, thereby adding a personal bond to the strategic relationship.

But nearly all of those 20th century rationales are now under strain.

The Cold War is over, Israel’s stability has now been virtually constant since the end of the Yom Kippur War in 1973 and the Camp David settlement between Egypt and Israel in 1978 and, most important of all, the United States may become energy independent within the end of the decade, thanks to new technologies to extract oil and natural gas through offshore, shale and oil sands and the greater proficiency of renewable energy technologies.  Though Saud Al Faisal (pictured above) has survived as the kingdom’s foreign minister since 1975, Bandar returned to Riyadh from the United States in 2005, and the Obama administration’s ties to the House of Saud aren’t nearly as warm as during either of the Bush presidencies or even the Clinton presidency.  The kingdom itself is stuck in somewhat of an arrested generational transition.

Among the three leading countries in the Organization for Petroleum Exporting Countries, Saudi Arabia was the only game in town for nearly the past four decades.  Sure, Saudi Arabia (8.8 bbl/day) leads both Iran (4.2 bbl/day) and Iraq (3.2 bbl/day) in oil production, and therefore gives it an even more powerful role in conditioning the world energy market.  But Iraq’s increasing belligerence under Saddam Hussein (and the instability that resulted from the 2003 US invasion) and Iran’s anti-American, anti-Israeli Islamic regime prevented a truly stable realpolitik partnership between the United States and Iran or Iraq.

Though US relations with Iraq and Iran remain complicated, there’s reason to believe that both bilateral relationships are on the mend.  Moreover, the Arab Spring revolts have forced the United States to take more sympathetic positions to grassroots agitation for greater political participation and human rights in the Middle East, and that’s put the United States at odds with the Saudis.  The kingdom was less than enthusiastic about Egypt’s experiment with democracy and the short-lived presidency of Mohammed Morsi, and they also backed Bahrain’s Sunni House of Khalifa in its violent crackdown against Shiite protestors in 2011 and 2012.  The Saudis would also love to see the end of the Assad regime in Syria, which has long aligned itself with rival Iran.

As the Middle East shows signs of coming into its own period of political awakening, and as the United States becomes less dependent on the region for its oil needs, the US-Saudi relationship was always bound to change.  The Saudi denunciation of its newly won Security Council seat may be a manifestation of tectonic and inevitable regional, economic and geopolitical shifts that will reduce Saudi Arabia’s longtime importance to the United States and therefore to the world.