President Obama listens to a translation during his joint news conference with Afghanistan's President Ashraf Ghani on Tuesday at the White House. (Jacquelyn Martin/Associated Press)

PRESIDENT OBAMA on Tuesday announced a much-needed adjustment in his plans for drawing down U.S. forces in Afghanistan, telling visiting President Ashraf Ghani that a scheduled halving of the 9,800 currently deployed troops by the end of this year would be set aside, and the force maintained into next year. This was a sensible response by Mr. Obama to a range of developments, including Mr. Ghani’s impressive efforts to improve relations with Washington. But the adjustment still falls short of what will be needed to give the new Afghan government a reasonable chance of success.

The president’s decision will allow for U.S. forces to remain at bases in eastern and southern Afghanistan that are critical for gathering intelligence and launching counterterrorism operations against al-Qaeda. It will also enable air and other logistical support to Afghan troops as they battle what is expected to be a fierce Taliban offensive this spring and summer.

Perhaps most important, Mr. Obama’s decision, accompanied by a commitment to fund Afghan military and police forces at their present levels through 2017, sends a message to the Taliban, which still hopes to overwhelm the Afghan army as U.S. support declines. The more the United States remains committed to continuing military aid to Mr. Ghani’s government, the more likely it is that Taliban leaders will finally respond to his persistent efforts to engage them in peace talks.

The problem is that Mr. Obama continues to offer encouragement to those in the Taliban who hope to outwait the United States. The president reiterated his plan to remove all but a few hundred U.S. service members by the end of his term. As his contrary decision to delay this year’s drawdown attests, that plan has less to do with conditions in Afghanistan than with Mr. Obama’s personal timetable.

The plan is misguided. While the Afghan government was roiled by months of controversy over last year’s presidential election, the Taliban was growing stronger. According to the United Nations, more than 10,000 civilians died in last year’s fighting, a record, while U.S. officials described Afghan military losses as unsustainable. The departure of all U.S. troops in 2017 would invite another Taliban surge; Mr. Obama’s legacy could be not another war ended but another failed state.

As it stands, neither the military nor the political situation is hopeless. Mr. Ghani and Chief Executive Abdullah Abdullah have made progress since settling their election dispute and taking office together in September. They have transformed the dysfunctional relationship with Washington they inherited from former president Hamid Karzai; at the Afghans’ impetus, a new U.S. economic aid program will be linked to government reforms that strengthen institutions and combat corruption. Despite its losses, the Afghan army has survived the withdrawal of more than 120,000 U.S. and allied troops.

Mr. Obama’s recalibration for the near term will help to ensure that the Afghan government survives another year of Taliban assaults and might help start peace talks. But the country’s long-term prospects remain hostage to the president’s ideological rigidity. Mr. Ghani, meeting with reporters and editors at The Post after his White House session, expressed gratitude for U.S. “flexibility” and then offered some common sense about future military plans: “When things can be done sequentially, let’s not preempt options.”