By FOUAD AJAMI

‘The tide of war is receding, and the soul of Baghdad remains, the soul of Iraq remains,” Vice President Joe Biden said at Camp Victory, by the Baghdad airport, earlier this month, in the countdown to the official end of the Iraq war. In truth, the receding tide Mr. Biden glimpsed was that of American power and influence in Iraq and in the Greater Middle East.

This wasn’t something the people of that region pined for. These are lands that crave the protection of a dominant foreign power as they feign outrage at its exercise. Nor was it decreed by the objective facts of American power, for this country still possesses all the ingredients of influence and prestige. It was, rather, a decision made in the course of the Obama presidency—the ebb of our power has become a self-fulfilling prophesy.

America was never meant to stay in Iraq indefinitely. In all fairness to President Obama, he had ridden the disappointment with Iraq from the state legislature in Illinois to the White House. He was not a pacifist, he let it be known. He did not oppose all wars. It was only “dumb” wars he was against. In every way he could, he kept Iraq at arm’s length. He never partook of the view that we had secured strategic gains in that country worth preserving. It was thus awkward to watch the president on Monday, with Iraqi Prime Minister Nouri al-Maliki by his side, explaining as we exit that “We think a successful, democratic Iraq can be a model for the entire region.” The words rang hollow.

A president who understood the stakes would have had no difficulty justifying a residual American presence in Iraq. But not this president. At the core of Mr. Obama’s worldview lies a pessimism about America and the power of its ideals and reach in the world.

The one exception to this strategic timidity is the pride Mr. Obama takes in prosecuting the war against terrorists. In a moment evocative of George W. Bush, Mr. Obama last week swatted away the charge that he had been appeasing America’s enemies abroad: “Ask Osama bin Laden and the 22 out of 30 top Al Qaeda leaders who’ve been taken off the field whether I engage in appeasement.” Fair enough. But the world demands more than that, it begs for a larger strategic reading of things.

We shall never know with certainty what was possible and open to us in Iraq. On the face of it, the Iraqis wanted us out, and Mr. Maliki and his coalition had been unwilling to give our troops legal immunity from prosecution. But how we got there is less understood. The U.S. commanders on the ground thought that a residual presence of 20,000 soldiers would suffice to keep the order in Iraq and give the United States an anchor in that country. The White House had proposed a much lower figure, somewhere between 3,000 and 5,000. That force level would have been unsustainable, a target for the disgruntled and the conspirators.

No Iraqi government would run the gauntlet of a divided country, and a feisty parliament, for that sort of deal. Mr. Maliki may not be fully tutored in the ways of American democracy, but he is shrewd enough to recognize that this American leader was not invested in Iraq’s affairs.

Six years ago, when this war was still young and its harvest uncertain, a brilliant Iraqi diplomat and writer, Hassan al-Alawi, wrote a provocative book titled “al-Iraq al-Amriki” (“American Iraq”). It was proper, he observed, to speak of an American Iraq as one does of a Sumerian, a Babylonian, an Abbasid, an Ottoman, then a British Iraq. He didn’t think that America would stick around long in Iraq, but he thought the American impact would be monumental. Whereas British Iraq empowered the Sunnis, the Americans would tip the scales in favor of the Shiites.

All three principal communities in Iraq had a vested interest in American protection. The Kurds, the most pro-American population in the region, were desperate to have America remain—a balance to the power of Turkey, a buffer between their autonomous zone in the north and the Baghdad government. The Sunnis, the erstwhile masters of the country, had come around: An American presence with enough authority would be their shield against a sectarian, Shiite regime that would cut them out of the spoils.

Ironically, the Shiite majority, the followers of the radical cleric Moqtada al-Sadr aside, had a vested interest in an American deterrent on the ground. For all their edge in the politics of Baghdad, the Shiites are still given to a healthy measure of paranoia about the world around them. The Iraq midwifed by U.S. power had been delivered into a hostile neighborhood. The Sunni Arabs had yet to accept and make their peace with the rise of a Shiite-led government in Baghdad. And the rebellion in Syria added to the uncertainty, feeding the anxiety of Mr. Maliki and the Shiite political class over a Syrian regime to their west ruled by the Sunni majority. There is also Turkey, large and now with economic means and a view of itself as a protector of the Sunnis of the region.

And there remained Iran, to the east, with the traffic of commerce and pilgrimage, with the religious entanglements born of a common Shiite faith. For the Sunni Arabs—and for Americans who had opposed this war—Iraq is destined to slip, nay it has already slipped, into the orbit of the Persian theocracy. The American war, with all its sacrifices, had simply created a “sister republic” of the Persian state, it is said.

Those who love to organize an untidy world have spoken of a “Shiite crescent” that stretches from Iran, through Iraq, all the way to the Mediterranean and Syria and Lebanon. But the image is false. Iraq is a big and proud country, with a strong sense of nationalism, and oil wealth of its own. An Iraqi political class, with its vast oil reserves, has no interest in ceding its authority to the Iranians.

The Shiism that straddles the boundaries of the two countries divides them as well. The sacred lands of Shiism are in Iraq, and the Shiism of the Iraqis is Arab through and through. The pride of Najaf is great, I can’t see it deferring to the religious authority of strangers.

One of our ablest diplomats, Ryan Crocker, then ambassador to Baghdad, now our envoy in Kabul, once pronounced the definitive judgment on these contested Iraqi matters: “In the end, what we leave behind and how we leave will be more important than how we came.” It so happened that when it truly mattered, the president who called the shots on Iraq had his gaze fixated on the past and its disputations.

Mr. Ajami is a senior fellow at Stanford’s Hoover Institution and co-chair of Hoover’s Working Group on Islamism and the International Order.