The United States went to war in Afghanistan in 2001, Iraq in 2003, and Syria—sometime after 2011, depending on how we define “war” in this era of ill-defined and boundless U.S. engagement in hostilities the world over.

In the early days, American involvement in Syria’s chaos was mostly remote. As Syrian President Bashar al-Assad’s brutal suppression of civilian protests devolved into civil war, then-President Obama called for regime change, closed the U.S. embassy in Damascus, drew a red line around chemical weapon use, and unsuccessfully petitioned Congress for authority to attack. Since then, the rise and fall of the Islamic State has seen a gradual expansion of American presence on the ground in Syria, beginning with airstrikes plus arms and training for comparatively moderate militants and escalating from there.

Today, there may be as many as 4,000 U.S. boots on the ground in Syria. Airstrikes continue, and though they have slowed since last year’s peak, the Trump administration has now twice bombed regime targets. And while ISIS is all but vanquished, Syria’s civil war grows all the more complex. U.S. forces now find themselves dodging (with varying degrees of success) conflict with Russian and Iranian troops backing Assad while Turkish soldiers—our NATO allies—are fighting U.S.-backed Kurds. President Trump says he wants to bring American soldiers home, but his administration has spuriously boasted of authority to keep them in Syria indefinitely.

Whether there was ever anything worthwhile to be gained by U.S. military intervention in Syria’s near-decade of conflict may be subject to debate, but it is increasingly evident there is no good reason to stay there now. In Syria, the United States finds no reward, only risks. It is time to make our exit.

The gravest plausible risk, of course, is greatpower conflict with Russia. Trump’s overtures to Moscow may be read as creative diplomacy or evidence of corruption—that is a question for another day—but either way they are unlikely to stave off war if American and Russian troops make a habit of shooting and bombing each other in Syria. The prospect of facing overwhelming U.S. military might will persuade American adversaries to accept some degree of losses at U.S. hands—see, for example, Moscow’s disownment of the Russian mercenaries who attacked and were killed by American and Kurdish forces in Syria in February. But the longer foreign troops supporting opposing sides in this civil war remain near each other, the greater the chance we reach a tipping point that slides us into full-blown war.

But this sort of catastrophic escalation is not the only way that continued U.S. intervention in Syria may have unwanted and unintended results. Trump campaigned against the nation-building of past administrations, but the longer the United States stays in Syria and the more changes we effect, the more we will own its eventual reconstruction.

To be sure, Syria will need reconstruction. Its physical destruction—to say nothing of the enormous human suffering this war has entailed—is so thorough it is difficult to comprehend. Yet if the past 17 years of U.S. foreign policy have demonstrated anything, it is that our government, and especially our military, is neither built nor equipped for Mideast nation-building.

As in Afghanistan and Iraq, where reconstruction has been a morass of waste and confusion, nation-building in Syria will at best be expensive and frustrating. More likely it will be counterproductive as well, as Syrians, whether loyalists to a toppled Assad or rebels seeking self-governance, come to see Washington as a foreign overlord, an occupier to be resented and resisted.

The recklessness of keeping U.S. soldiers in harm’s way in Syria is compounded by the fact, often sidestepped by Washington, that there are no vital American interests at stake. Regional powers like Russia, Iran, Turkey, and, recently, Israel may intervene in Syria out of fear that its violence will spill across their borders. That cannot happen to the United States.

Assad is “a particularly contemptible despot,” notes military historian Ret. Col. Andrew Bacevich—but then, Saddam Hussein was a contemptible despot, too. His U.S.-forced ouster “produced an epic disaster. Costs vastly exceeded benefits.” Thousands of Americans and hundreds of thousands of Iraqis lost their lives, and ordinary Iraqis continue to live with enormous instability and violence today. In Syria, likewise, Bacevich says, “employing violence as an antidote to Arab repression has proven to be a bust. So anyone proposing that the United States have another go at it, this time targeting Assad, should think long and hard. We don't need more war in the Middle East. War hasn't worked.”

A message from Washington to Syrian rebels this week suggests the Trump administration may have an inkling of that futility. “[Y]ou should not base your decisions on the assumption or expectation of a military intervention by” the United States, the communique warns. Instead, in Reuters’ paraphrase, it tells “the rebels it was left to them alone to decide how to face the Syrian army’s military campaign based on what they saw was best for themselves and their people.” This may not be the message the rebels hoped to receive, but after the last 17 years, it is the message America must send.