Democratic leaders on Capitol Hill are applying fresh pressure on the Obama administration to draw down U.S. troops in Afghanistan faster than many military leaders say is responsible, forcing the president to balance his party’s demands with his generals’ on-the-ground assessment as he nears another milestone in the war.

When he announced his war strategy 18 months ago, President Obama set July as the point when he would begin bringing home the approximately 100,000 U.S. service members in Afghanistan. Administration officials have portrayed the reduction as just another planned step in the president’s strategy.

But Sen. John F. Kerry, chairman of the Senate Foreign Relations Committee, is among a growing number of congressional leaders urging Obama to take full advantage of progress achieved over the past 18 months by narrowing the mission’s focus.

These lawmakers argue that, at a time of fiscal stress at home, the administration should concentrate on targeting al-Qaeda and protecting other U.S. security interests in the region, rather than on maintaining the broad military deployments across much of southern and eastern Afghanistan and the costly nation-building elements of the counter-insurgency strategy.

This political push could force the White House to revisit a contentious internal debate that unfolded in fall 2009, when Obama’s civilian advisers challenged the uniformed military over how best to change the course of a flagging war effort. But Obama is now making his decision amid a difficult reelection effort and when the killing of Osama bin Laden has made some lawmakers argue that the time is ripe to dramatically scale back the U.S. war effort.

“The president ought to take advantage of that success and push us in a direction that accelerates the ability of the Afghans” to take over operations, said Kerry (D-Mass.).

Obama is awaiting a set of recommendations from his military commanders on how many troops to bring home in July and the pace of withdrawal over the months ahead. Defense Secretary Robert M. Gates, who on Friday concluded an 11-day trip that took him to Afghanistan, could deliver Gen. David H. Petraeus’s proposed options to Obama in the next week.

“The president obviously is very mindful of how we use our resources and setting priorities for how we use our resources,” White House spokesman Jay Carney told reporters Thursday. “The fact is that we believe we are making progress. . . . And when he announces the decision he makes in terms of the drawdown, I’m sure he will also put it in the context of the implementation of the strategy he put in place in December 2009.”

That month Obama announced his decision to send an additional 30,000 troops to Afghanistan, largely adopting a surge strategy recommended by the military leadership.

For his civilian advisers worried about the scope of the escalation, Obama also set next month as the beginning of the end of the surge. As that deadline approaches, the argument over how quickly or slowly to leave a nearly decade-old war is intensifying.

When he adopted the strategy in 2009, Obama was a relatively new commander in chief still working out his relationship with his commanders. Obama has more experience as a wartime leader today, and his risky decision to authorize the raid deep inside Pakistan that killed bin Laden last month has burnished his reputation as a president who has faith in his military. Outside analysts say he may feel more able to turn down his generals’ advice.

The debate over how many troops to pull out next month has been far more muted than that months-long, leak-filled 2009 strategy review. White House officials say Obama, who receives a weekly Afghanistan update from the State Department and runs a monthly session on the war with his senior national security team, does not need an extensive internal debate or review to make this decision.

“The debates are going to be about the specifics of implementing the strategy we have embarked on. I don’t really see why we’d be focusing on revising it,” said a senior administration official who, like others interviewed, spoke on the condition of anonymity to describe internal White House discussions.

The official said that there is “huge pressure on the Taliban” and that an “Afghan-led political process that didn’t exist before is taking some shape. Al-Qaeda is on its heels; bin Laden is dead.”

“Right now, when we do these discussions, we’re looking at how do you sustain these gains and do the transition in a way that maximizes the chances of keeping the American people safe,” the official said.

But in recent weeks, a pair of high-profile proxies have emerged representing the two sides of the administration’s internal discussion over the pace of the troop withdrawal — Kerry and Gates.

Kerry has called the war’s $10 billion-a-month cost “unsustainable,” and on Wednesday, his committee issued a report critical of the economic assistance program that is a key part of the counterinsurgency strategy’s goal of bringing stability and government to parts of the country once controlled by the Taliban.

Kerry is a longtime friend and former Senate colleague of Vice President Biden, who in the 2009 war strategy review argued for a smaller U.S. military mission in Afghanistan that would focus on weakening a-Qaeda, rather than on defeating the indigenous Taliban insurgency.

With bin Laden’s death, the civilian advisers who favor that approach, led by national security adviser Thomas E. Donilon, have a fresh argument for a more targeted — and less expensive — military mission at a time of severe fiscal strain at home. A second senior administration official said, “Kerry is obviously someone who is respected here, and he would be heard,” adding that others would be as well.

In an interview, Kerry said that “part of the struggle here is to get people here, my colleagues included,” to focus on “what is the objective.”

“What I would urge, and what the president needs to think about here, is what is the best way now to take advantage of that so that you don’t go backwards, but that you also don’t necessarily stick with the kind of reach that you had because you don’t need to,” he said. “I don’t see this as changing the current strategy because it’s somehow not working.”

But Gates has said that Obama should move cautiously in removing troops from a battlefield where the gains, in the White House’s own assessment, remain “fragile and reversible.” Obama has relied on Gates as a trusted liaison to the uniformed military, and he ends his five-year tenure this month.

“I can tell you there will be no rush to the exits,” Gates said Friday in a speech in Brussels.

He went on to say that “the vast majority of the surge forces that arrived over the past two years will remain through the summer fighting season.”

“Far too much has been accomplished, at far too great a cost, to let the momentum slip away just as the enemy is on its back foot,” he said.

While White House officials say electoral politics is not a factor in the decision, Obama is campaigning for reelection next year at the head of a party deeply opposed to the Afghanistan war.

Bringing home the surge troops by the end of the year would allow Obama to demonstrate to his party, particularly its liberal grass roots, that he is winding down the war in Afghanistan, just as he has in Iraq.

Advisers say he will probably use his commanders’ recommendations as a base line to draw from, adopting some elements and coming up with others of his own, as he did in 2009. They say there is no timeline for the decision or for his speech outlining the path ahead, other than his commitment to withdraw the first surge troops before the end of July.

“He knows this is the longest war we’ve been in and there’s war weariness in the country,” the second senior administration official said. “This isn’t about people getting his ear and persuading him. He understands. And he wants the strategy he put in place to succeed.”