Against a backdrop of repeated failures to militarily quell the Afghan insurgency, United States President Barack Obama announced a change of course and decided to keep 9,800 troops that would have been withdrawn next year and leaving 5,500 for 2017 or beyond.

The decision to withdraw the last American soldiers is now left to his successor. A New York Times op-ed last month asked:

"Are we losing Afghanistan again?"

The Taleban responded to the announcement with a defiant statement, that "withdrawal of foreign forces still remains a prerequisite" for any political settlement of the conflict - a position it has vehemently held since the United States first ousted it from power in 2001.

The proposal to delay withdrawals, also announced by Afghan President Ashraf Ghani earlier in the year, was mainly backed by General John Campbell, the US commander in Afghanistan.

Though under consideration for some time, the stunning capture of the provincial capital of Kunduz, bordering Kyrgyzstan, by the Taleban recently may actually have influenced the timing of the presidential announcement.

Increasingly adverse circumstances have compelled President Obama to go back on his commitment to extricate the US from this 14-year war that it is nowhere close to winning.

In maintaining the troop levels, the US administration hopes to instil much-needed capacity in the Afghan National Defence and Security Forces (ANDSF) so that they are able to withstand and roll back, if possible, the increasingly confident Taleban.

The decision to delay troop redeployment is an acknowledgement by the US that the ANDSF, on which it has spent an estimated US$65 billion (S$91 billion) since 2001, is unable to subdue the militants. And yet military-oriented US thinking focuses only on victory over the perceived enemy.

It is still questionable how this small force can make a difference against a resurgent Taleban when a much larger one could not quell it since 2001.

Highly placed sources reveal that Afghanistan lives with about 100 big or small militant-related acts of violence every day.

This is a stinging rebuke to any claims of stabilisation of the Afghan national unity government that is just about to complete its first year in power.

Brokered by the US, the government in Kabul - jointly run by bitter rivals President Ghani and Chief Executive Abdullah Abdullah - suffers from factional paralysis. Key appointments remain pending in the wake of disagreement between the two. Both understand the necessity of the US military presence for the government's survival.

The United Nations has determined that the Taleban threat to half the country is "high or extreme". This is more territory it has controlled after 9/11. Last month, security forces battled the Taleban to push it back from Helmand province, closer to its strongholds in the south.

In the Taleban seizure of Kunduz, reports indicate that Taleban cadres nested there with the locals for days and then, in an inside-out attack, captured the city.

That they evaded the ANDSF to enter and nest in the city with their weapons confirms that the security men were either in collusion, incompetent, or just ill-prepared to deal with a guerilla force. And notwithstanding the money and training received, many in the national force retain loyalties with their tribes and warlords.

The city was retaken only after active US Air Force and Special Operations Forces support.

That a few hundred Taleban fighters were able to take the provincial capital echoes the fate of similarly trained Iraqi troops, who melted in the wake of attacks by Islamic State in Iraq and Syria militants last year.

Circumstances have therefore compelled President Obama to go back on his commitment to extricate the US from this war.

The US strategic planners caught in the Afghanistan maze are still unable to understand the big difference between Iraq and Afghanistan.

In Iraq, the US dislodged a regime run by a minority community that allegedly discriminated against the majority.

In Afghanistan, the US ejected a regime based on majority Pashtuns and brought in a minority government dominated by rival ethnic groups like Tajiks, Uzbeks and Hazaras.

Since the fiercely nationalist Pashtuns form a majority of the Afghan population, no arrangement that excludes them will hold. Herein lies the big reason for the American failure.

In deciding to maintain troops in Afghanistan, the US risks getting sucked into this battleground again, just as there is talk of reinforcing the American role in Iraq by thousands of additional troops.

Each step in the direction of military engagements calls for more to achieve an elusive victory.

No foreign army beginning with Alexander the Great has been able to hold this "graveyard of empires".

The US should listen.

• Sajjad Ashraf is an adjunct professor at the Lee Kuan Yew School of Public Policy, National University of Singapore. He was Pakistan's High Commissioner to Singapore from 2004 to 2008.