The longest war in American history ended quietly last month, with a Kabul ceremony marking the formal transition from NATO’s combat mission to a period of limited support for Afghan security forces. Following their German and British counterparts, who withdrew in the waning months of 2014, a vast majority of American troops are withdrawing from the country. From a high of 140,000 soldiers in 2010, the American contingent is being reduced to a residual force of 9,800, which will continue to dwindle in the coming two years. By 2016, a negligible number will remain.

The Afghanistan War certainly doesn’t feel like a victory. There was little triumph and a great deal of fatigue apparent in President Obama’s manner as he announced the war’s impending end in the Rose Garden last May. The United States has paid for its protracted intervention with 2,224 soldiers’ lives and ov­­er $1 trillion in war debt. Yet there have been important gains. The NATO coalition overthrew a brutal Taliban regime, and facilitated the rise of a genuinely, if imperfectly, democratic government. According to the Long War Journal, military reports indicate that the security situation throughout the country is much improved — most dramatically in northern tribal regions where attacks have declined by 60% but also in and around southern population centers. The Afghan police force and military have grown from the ground up to a combined strength of 350,000.

These hard-won victories, however, are exceptionally fragile. A New York Times interview piece with Lieutenant General Joseph Anderson, shortly before his departure from the country last month, indicates that Afghan security forces were hard-pressed to shoulder the brunt of the conflict last year. They suffered a record 5,000 casualties, along with unsustainable rates of desertion, he said. An April Department of Defense report corroborated Anderson’s negative assessment.

“Logistics and sustainment capabilities remained underdeveloped, Afghan National Army attrition was higher than its target, and corruption continued. Although the International Security Assistance Force continues to develop capabilities, ANSF requires more time and effort to close four key high-end capability gaps that will remain after the ISAF mission ends on December 31, 2014”

Unsurprisingly, in light of these facts, many have displayed misgivings about the hard 2016 pullout deadline that President Obama has enacted.  Not least of them is Afghan President Ashraf Ghani. “Deadlines should not be dogmas,” he said in a recent CBS interview. “[If] multiple partners have done their best to achieve the objectives and progress is very real, then there should be willingness to re-examine a deadline.” Former Army Vice-Chief of Staff Jack Keane was more direct. “Arbitrarily pulling those forces out absolutely risks successful completion of the mission,” he told the New York Times.

The United States has learned a hard lesson in recent years about the consequences of prematurely abandoning its conflicts. After leaving Iraq wholesale in 2011, despite the expressed desire of every major Iraqi party leader that a residual American force remain, the United States was forced to look on as the country descended into fresh spasms of sectarian violence, before falling prey to invasion by the Islamic State. ISIS now controls tens of thousands of square miles in northern Iraq — including the country’s second-largest city, Mosul. Now the United States has re-kindled its intervention with air strikes, but there remains little promise of re-capturing occupied territory without a robust ground presence.

“This is how wars end in the 21st century,” President Obama said in his Rose Garden address.  “Not through signing ceremonies, but through decisive blows against our adversaries, transitions to elected governments, security forces who take the lead and ultimately full responsibility.” He was right, of course. Asymmetrical wars do not end cleanly, with unconditional surrenders offered by defeated parties. The United States will never leave Afghanistan in the assurance that the enemy have been entirely eradicated. But to secure our objectives there — which are both tangible and worthwhile — President Obama must not prioritize the political capital he stands to gain by ending an exhausting war over his duty to end it in a truly responsible manner.

THURSDAYS WITH THOMAS is published weekly. Columnist Thomas Toghramadjian engages readers in topics ranging from politics to literature to science.