President Obama will announce in a prime-time address Wednesday his decision on how many troops to withdraw from Afghanistan next month, concluding a process of consultation with his advisers and commanders that will set the military course for the rest of the war.

Administration officials said final numbers, while still to be determined, will chart the glide path for further withdrawals between now and the end of 2012, a period when Obama will face a reelection fight. Polls show that a majority of Americans believe the nearly decade-old war is no longer worth fighting.

The announcement will set a withdrawal schedule for the 33,000 “surge” troops Obama sent to Afghanistan early last year as part of an escalation that his commanders say has succeeded in clearing Taliban fighters from key areas in southern Afghanistan.

That decision put Obama at odds with some civilian advisers, who favored a more focused counterterrorism effort rather than the military’s expansive counterinsurgency campaign designed to stabilize the weak Afghan state.

In his Wednesday speech, Obama will remind Americans of the reasons behind the escalation and the rationale for keeping tens of thousands of troops in the country at a time of fiscal strain at home. Although Obama has yet to make a final decision on how many troops to remove in July, administration officials say the number is likely to fall between 3,000 to 5,000, including some originally scheduled to deploy to Afghanistan but will instead stay home or be sent elsewhere.

The administration had hoped to couple Obama’s announcement on troop withdrawals with news of progress on political reconciliation with Taliban leaders. But discussions have stalled after several rounds of talks this spring between U.S. officials and Taliban interlocutors, first in Qatar and later in Germany.

In recent meetings with the president, military leaders have requested that most of the surge forces remain in the country through the end of next year. As one administration official put it, “The commanders think in terms of fighting seasons, and that would give them two more full ones with the bulk of these troops.” Officials spoke on the condition of anonymity to discuss internal White House planning.

But Obama informed senior advisers on Monday morning that he has yet to reach a final decision on how many troops to withdraw and over what time. The official said the president “could slow down or accelerate” the withdrawal pace that military commanders have asked for.

White House officials are still working through the specifics of Wednesday’s speech, including the venue. Administration officials have not decided on the room in the White House where Obama will address the nation, though one official said it will not be from the Oval Office. They have sought to play down the significance of this moment in the war, saying the beginning of the withdrawal is just another milestone in the president’s strategy.

“While we don’t see this as a major inflection point, it is an important moment to communicate with the American people about Afghanistan,” the official said.

On Thursday, Obama will travel to Fort Drum in Upstate New York, where he will visit with troops. The post is home to the Army’s 10th Mountain Division, which has been deployed in the Iraq and Afghanistan wars.

The number and pace of the withdrawals, from a current total of about 100,000 troops, has been a contentious issue within the White House and between the administration and the military, which has warned against a significant drawdown before gains of the past year are solidified.

Obama has been under conflicting pressure on the pace of withdrawals from his own advisers, some of whom think that the broad civil-military campaign in Afghanistan has overreached and have argued that the killing last month of Osama bin Laden in Pakistan has greatly weakened al-Qaeda.

Outside the White House, lawmakers and a war-weary public have voiced their own opinions about what the president should do. In a resolution passed Monday in Baltimore at its annual conference, the U.S. Conference of Mayors urged Congress to quickly end the wars in Afghanistan and Iraq and spend the money — about $112 billion this year in Afghanistan alone — on jobs at home.

Senior Democrats in Congress, and many Republicans, have questioned the major troop deployments, called the costs unsustainable and urged a rapid withdrawal. Senate Armed Services Committee Chairman Carl M. Levin (D-Mich.) has suggested that Obama withdraw 15,000 troops by the end of the year.

Republican hawks, however, have criticized that number as much too high; Sen. John McCain (Ariz.), the senior Republican on the committee, has said the number should be closer to 3,000. In a debate last week, seven Republicans contesting the party’s 2012 presidential primaries were divided about how to proceed, with most calling for the troops to come home.

Accompanying the troop surge, the State Department has tripled the number of civilians working in Afghanistan, to more than 1,130, and spent $19 billion there since 2002. Congressional budgeters are expected to substantially cut the department’s $3.2 billion request for Afghanistan for fiscal 2012.

In addition to its development work on the ground in Afghanistan, State has been leading talks with the Taliban that the administration hopes will eventually bring the war to a political settlement.

But that outcome is still seen as years away, with little progress since preliminary meetings this spring. The Taliban was represented by Tayyab Agha, well-known during during the late 1990s as a spokesman and close personal aide to Taliban leader Mohammed Omar. Now believed to be in his mid-30s, Agha last appeared in public in November 2001, when he denied in a meeting with Western journalists that the Taliban had been defeated by Afghan and Western forces. Both Omar and Agha are believed to have been in Pakistan since then.