Arthur Schlesinger posited the existence of cycles in American political history alternating between “public purpose” and “private interest”—his jaundiced labels for liberalism and conservatism. There are also cycles in American foreign policy alternating between interventionism and noninterventionism, the latter sometimes verging on downright isolationism. Normally when one trend backfires in some spectacular fashion, the other trend becomes dominant, until it too burns out and the cycle starts again.

Thus the interventionism of 1917-1918—when 116,000 Americans died to “make the world safe for democracy,” and military regimentation was imposed on the home front—led to a quest for “normalcy” in the 1920s, which eventually morphed into isolationism in the 1930s. That retreat from the world, which ignored the rise of Nazi Germany and Imperial Japan, was followed by the all-out mobilization of World War II. After the defeat of the Axis at great cost, including 417,000 American lives, the United States demobilized, only to rearm once again following the outbreak of the Korean War in 1950.

John F. Kennedy’s inauguration on a promise to “pay any price, bear any burden . . . in order to assure the survival and the success of liberty” led to the Vietnam war and the death of 58,000 soldiers. The trauma of Vietnam was responsible for a quasi-isolationist decade in the 1970s, which ended in the humiliation of the Iranian hostage crisis and set the stage for a defense buildup and a more assertive foreign policy under Ronald Reagan.

After the American victories in the Cold War and Gulf war, Bill Clinton downsized the military and concentrated on domestic priorities. George W. Bush planned to do the same, but following 9/11 he undertook ambitious interventions in Afghanistan and Iraq, which left more than 6,700 American troops dead and tens of thousands wounded and cost trillions of dollars.

Which brings us to where we are today in the cycles of American politics: in a disengagement phase, sometimes camouflaged as “leading from behind.” President Obama has vowed to “rebalance” our commitments, from the Middle East to the Pacific. But the rebalancing has often looked like a full-blown American retreat from the most conflict-torn region in the world.

The president pulled U.S. troops out of Iraq and showed little interest in shaping Iraqi politics thereafter, a task he delegated, along with other unpleasant chores, to Vice President Biden. He lost faith in his own surge in Afghanistan, according to Robert Gates’s memoir, and pulled the plug earlier than commanders on the ground thought prudent. Obama now plans to leave only a small residual force in Afghanistan after 2014—and maybe not even that if Hamid Karzai refuses to sign a security accord soon.

Obama refused to become heavily engaged in Syria. After months of dithering, he almost ordered airstrikes last year in retaliation for Bashar al-Assad’s use of chemical weapons but then backed down and agreed to a deal to eliminate Assad’s chemical weapons arsenal in return for tacit American approval for the continuation of his rule. Obama did use American airpower to help overthrow Muammar Qaddafi but kept allies in the lead and refused to engage in nation-building afterward. He has refused to strike the Iranian nuclear facilities, as urged by allies such as Israel and Saudi Arabia, preferring to make a deal with the mullahs, whom he also hopes to draw into negotiations to end the Syrian civil war.

And Obama has presided over a substantial decline in defense spending, which is due to be reduced by $1 trillion over the next decade, or roughly 30 percent from projections at the beginning of the administration. This has led to a readiness crisis that recalls the hollow army days of the 1970s.

All this Obama has done with approval from a war-weary public. A recent Pew poll finds that 52 percent of those surveyed think “the U.S. should mind its own business internationally and let other countries get along the best they can on their own”—the first time since 1964 that more than half of respondents have taken such a stance.

Clearly, the noninterventionist cycle is far advanced. And, like the interventionist phase that preceded, it has gone too far, setting the stage for a backlash that could augur a new era of more activist foreign policy. This is not a prediction that U.S. foreign policy will change overnight (it will probably take another presidential election to effect major change), but it is increasingly obvious to observers of all political hues that the costs of American nonintervention have been high.

Iraq, Syria, Lebanon, Egypt—indeed the entire Middle East—are in a worse state than ever. Al Qaeda fighters are parading through Fallujah, car bombs are going off in Beirut, barrel bombs are being dropped on Aleppo.

Iran and its proxies in Hezbollah are stronger than ever, having gone all-in to preserve Assad in power while the United States has dithered on the sidelines. Iran has 19,000 centrifuges spinning and is closer than ever to acquiring nuclear weapons, free of any effective threat of American military action. Tehran’s nuclear ambitions may be slowed but are unlikely to be abandoned by a deal with the United States, which ratifies its supposed “right” to enrich. Even while negotiating with Washington, Iran is supplying Hezbollah with long-range rockets and the Bahraini opposition with arms.

On the other side of the sectarian divide, al Qaeda and its fellow-travelers are stronger than ever, with Sunni jihadists freely operating in western Iraq and northern Syria, and even in Lebanon, where they are matching Hezbollah car bomb for car bomb. Saudi Arabia and the Gulf states are so disgusted with U.S. foreign policy that they are pursuing their own path, which is drawing them into a de facto alliance with jihadists from Iraq to the Levant.

Much of this, it goes without saying, is due to the internal dynamics of the region’s dysfunctional states, but the United States has had a role in stoking the conflict. Democrats want to blame all this on Bush for invading Iraq, but that explanation is wearing thin five years after Bush left office. It’s true that Bush made a hash of Afghanistan and Iraq initially, and that the ripple effects of his early blunders are still with us. But he also set in motion a surge in Iraq that reduced violence by 90 percent and made it possible to imagine a more stable, democratic state developing out of the rubble. Except perhaps in Kurdistan, that promise has now been lost, in no small part because of Obama’s unwillingness to follow up.

Things might have gone very differently in Iraq if Obama had gotten personally involved after the 2010 hung election by lobbying for the selection of Ayad Allawi, a nonsectarian Shiite acceptable to Sunnis, as prime minister rather than rubber-stamping, in cooperation with Iran, the reelection of the more sectarian Nuri al-Maliki. So, too, things might have been different if Obama had launched a full-court press early on to win Iraqi agreement for U.S. troops to remain after 2011. In the judgment of many knowledgeable observers, Iraqi politicos could have been brought around to support a U.S. troop presence, had not Obama chosen to pull the plug on negotiations after some initial difficulties over immunity from Iraqi laws. A more activist American government might have prevented the emergence of a poisonous rift between a Shiite sectarian regime in Baghdad and the Sunni sheikhs of Anbar Province—a rift that has been exploited by Al Qaeda in Iraq to stage a dismaying resurgence.

In Syria, things might have been different if the president had decided to arm the moderate opposition at the start of the civil war in 2011, as urged by Secretary of State Hillary Clinton and CIA director David Petraeus. If such actions had been combined with the imposition of a no-fly zone, Assad’s regime might have been overthrown in relatively short order, as Qaddafi’s was. Instead the war has raged on and on, killing more than 120,000 people and destabilizing the neighboring states of Iraq and Lebanon. Syrian territory is now being divided by Hezbollah on the one hand and, on the other, Sunni extremist groups such as the Al Nusra Front and the Islamic State of Iraq and Syria.

All of these catastrophic trends have been evident for a couple of years, at least, but they have only caught the public eye now that al Qaeda fighters are, at least temporarily, in plain control of Fallujah, a city that American forces sacrificed much to pacify in 2004. Even the New York Times, on its front page, is making fun of Obama’s frequent boast, “I ended the war in Iraq,” because it is evident that Obama’s troop pullout actually restarted a war that had been all but extinguished.

It is time for the cycle to swing back to a more interventionist phase. There is an opening here for a presidential contender smart enough to grasp it. If history is any judge, the swing back to interventionism is coming, and soon. A smart contender would get out ahead of the cycle now by outlining how the United States can pursue a policy of strategically grounded, tactically adept international leadership.