What is happening between Saudi Arabia and the U.S.—the very fastest of friends since American geologists first caught the whiff of petroleum in the early 1930s? And how much should anyone worry about a rift between Washington and Riyadh?

The answer to the first question is, “A lot.” It is vital to come to terms with what looks like a serious split and recognize that it presents the Obama administration with a fundamental challenge.

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Washington and Riyadh have built and shared one of the bedrock relationships in the Middle East the whole of the postwar era. Now the Saudis are in open revolt as the White House rethinks policy across the region. We are probably looking at a new dimension of the seismic shift that set the Mideast awhirl (and a lot of it on fire) and launched the Arab Spring.

The answer to the second question is, “Not much.” The consequences of drifting ties between the U.S. and the Saudis will be desirable on the diplomatic plane, but there’s a caveat: This depends hugely on whether Obama and his advisers can recognize that policy renovation in the Middle East is overdue and that the House of Saud goes phobic at any hint of renovation—right down to women driving cars, you may have noticed this past weekend.

It is a little like friends or lovers—terrific if they can stick with you as you change, but if they cannot you have to leave them behind.

As to oil flows, it is doubtful this odd outbreak of pique will change anything at all. The U.S. now imports 1.3 million barrels of crude daily from Saudi fields. That is roughly average for the past quarter of a century, but it is well below the peaks—2.3 million barrels in 2001 and again in 2003—and the trend is clearly downward now.

Besides, the energy equation is changing on both sides. For Americans, domestic production of oil and natural gas—whatever one thinks of the technologies—is reducing import dependence. For the Saudis, alternative markets—China, India—have for years afforded Riyadh greater latitude in its foreign relations.

The big long-term factor concerns Saudi Arabia’s domestic consumption. It is growing quickly, and this reduces the nation’s role as the “swing producer” willing to compensate for supply drops when Washington imposes sanctions on Iran, say, or wrecks the Iraqi oil industry.

Get this: The Saudi reserve margin will drop to zero before 2020, according to a Riyadh investment house called Jadwa. It will consume all of its daily production of 12.5 million barrels by 2043; Chatham House, the London think tank, thinks the Saudis will have become net importers of oil five years earlier than that.

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It is not like the old days when the Saudis were America’s friends in need and the need was evident all too often. This is not to say Riyadh’s recent displays of anger can be ignored. They cannot. There is a lot to read into these astonishing moments.

I had never seen a petulant Saudi Arabian official before last week. The House of Saud, since it founded Saudi Arabia just about the time Americans sniffed the fumes of crude, has been the very model of discretion and regal detachment. Suddenly the outward composure falls away and it is all grievance and complaint.

First, Foreign Minister Saud al–Faisal, a prince in the ruling house, canceled his scheduled speech before the UN General Assembly earlier this month. This was a first. Two weeks later, the Saudis announced they would reject a rotating seat on the Security Council—this after a two-year campaign to build support.

Last week, Turki al–Faisal, another prince and a former intelligence minister, delivered a fiery attack on the Obama administration in Washington itself.

Riyadh has been highly anxious since the Arab Spring in 2011. The thought of democratically driven social change among Muslim-majority neighbors is profoundly threatening to the monarchy. This is why matters such as women drivers are not unrelated to Saudi policy in the region.

The Saudis were angry when Obama stepped back and let Egyptians depose Hosni Mubarak. They were angry again when the administration (finally, far too late) cut some aid to the Egyptian military after it took down the elected government of President Mohammed Morsi.

More recently they have been angry that Obama backed away from military intervention against the Assad regime in Syria. And most recently of all, Riyadh cannot bear the thought of a settlement with Iran on its nuclear program.

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The Saudis have not been standing still. They stepped in with $5 billion in aid when Washington threatened to cut off the Egyptian military. They are arming the Syrian rebels—never mind that many of them are jihadists who could well come to haunt the Saudi monarchy itself.

Part of Riyadh’s motivation is to tilt the regional rivalry between Sunnis and Shi’a Muslims in favor of the former. Saudis are Sunni. It also wants to prevent the rise—the unpreventable rise—of Iran as a regional power. Iranians are Shi’a.

Almost certainly part of this new impetuousness among high Saudi officials reflects their frustration that their influence over Washington is not significant, and there is no alternative pole of power toward which they could gravitate. Nonetheless, there are lessons in this for the Obama administration:

• There is no future in aligning with powers opposed to genuine, lasting evolution in the Middle East’s political institutions and social arrangements. The Arab Spring was all about the end of a long dark age. It is vital to interpret the Saudi question within this frame. Lining up on the Sunni–Shi’a conflict would be sheer folly.

• Riyadh is accustomed to comfortable survival courtesy of American power. In an opinion piece on the Al Jazeera site the other day, Mark LeVine, a scholar at the University of California, Irvine, termed the “special relationship” between Riyadh and Washington the “weapon-dollar-petrodollar coalition.” This is precisely what the U.S. has to leave behind in favor of policy rooted in diplomacy.

• Riyadh prefers American unilateralism to multilateralism of any variety. This is why the Saudis have pointed so much flak at the U.N. Again, the Saudi position is yesterday’s idea. Obama has been slow to re-evaluate Middle East perspectives and policies, but now that he is doing so, the imperative is to see where the future lies.

Some of Obama’s critics at home, including Karen Elliott House writing in the Wall Street Journal, are now adopting the Saudi theme, calling the president’s modest efforts to reinvent the American profile in the Middle East a measure of weakness. This does not stand up to scrutiny.

Maintaining status quo at any cost is not good diplomacy. “Stability” as a non-negotiable priority can be a false god. Skilled diplomacy, gutsy diplomacy, great diplomacy—and strength, not least—lie in the commitment to change when change is a necessity. Weakness is to cling to a washed-up strategy just because it is there.