No Middle East conflict is as complex as the one raging in Syria. The fight involves a government that is antithetical to Western values and a Sunni extremist insurgency that at one point captured the borderlands between Syria and Iraq and fought all the way to the gates of Baghdad. The stakes of the war are so high that a varied cast of foreign actors — including Russia, Turkey, Iran and Hezbollah — have all been drawn in.

But there are actually numerous wars being fought in Syria. One struggle, waged against the Islamic State terrorist group, is well known to the American public. Less understood is the war to succeed the House of Assad, which has ruled the country as a secular dynasty for almost 50 years. A third conflict involves northern Syria’s Kurds, who joined with the United States to fight IS but whose efforts have stoked fear among Turkish leaders that the aspirations of Syria’s Kurdish population could embolden the Kurds in Turkey.

Now add to this many-sided conflict a U.S. president who is uncomfortable with nuance or detail. Donald Trump neither possesses an internationalist mindset nor grasps the message that American power conveys. But while Trump could have been forgiven for arguing that America’s only interest in Syria was the defeat of IS, his decision to withdraw all U.S. forces — which he justified with an erroneous declaration of victory — is inexcusable.

Trump’s decision will embolden President Bashar Assad, whose rule has been catastrophic for Syria. Assad has consistently shown an inability to navigate the complexities of the crisis, including the rapid urbanization, and subsequent radicalization, of rural Sunnis displaced by climate change; the incubation of radicalized Sunnis in neighboring Iraq amid the consolidation of Shiite political power in Baghdad; and the growth of Kurdish nationalist sentiment in the region.

But Assad did know whom to call to maintain his grip on power, and the infusion of Russian, Iranian and regional Shiite groups was enough to turn the tide in his favor. That has given his regime a new lease on life in a region not accustomed to giving leaders second chances. And yet, Assad, like the French Bourbons, seems to have learned nothing and forgotten nothing during his 18 years in power and is unlikely to consolidate his victory by introducing the federalized, decentralized structures needed to govern Syria effectively.

U.S. policy in Syria, the policy that Trump campaigned against and has now officially abandoned, has long rested on two pillars: stability in Iraq and the defeat of IS. Under President Barack Obama, and then briefly under Trump, U.S. forces worked with local fighters to bring IS to heel. But, contrary to Trump’s claims, IS is neither defeated nor dead; absent viable institutions and stable political arrangements in Syria, the group is likely to return in some form.

Rather than acting unilaterally, as he apparently did, Trump should have been asking his foreign policy team for clarification on a number of thorny questions. What endgame should the U.S. be seeking in Syria? Given Assad’s support from Russia, Iran and Turkey (whose interests in Syria are hardly trivial), how likely is his departure? What political solutions are possible? Is an election feasible or desirable in a context devoid of functioning institutions?

But even posing these simple questions — which admittedly have no easy answers — seemed beyond Trump’s ability and range of experience. Instead of asking anything, Trump chose to declare victory and leave. That decision, and the expected withdrawal from Afghanistan and perhaps elsewhere, fits a familiar pattern: America’s engagements with the world are too often guided by a premature belief that the objective has been achieved.

But the withdrawal from Syria is more notable — and may be more damaging — than most, because it is being ordered by a U.S. president who clearly has no idea what he is doing and who is incapable of gauging his actions against the lessons of history. Facts are not knowledge and knowledge is not wisdom, but in Trump’s worldview, there is simply no room for the idea that history can both inform and repeat, or for the connections among many of the world’s most pressing security challenges, whether Syria, Russia or Iran.

Typically, U.S. foreign policy is viewed as a proxy not only for the president’s toughness, but also for his responsibility to use all resources at his disposal to grapple with matters of state and national security that the public may not see. But with Trump, there is none of that. The bluster and blunders that have become visible to all are as thoughtful and strategic as it gets.

Christopher R. Hill, former U.S. assistant secretary of state for East Asia, is chief adviser to the chancellor for global engagement and a professor of the practice in diplomacy at the University of Denver, and the author of “Outpost.” © Project Syndicate, 2018