But Obama did try to "dispense with the more extreme options on either side of the debate", as one administration official, speaking on condition of anonymity, put it.
Extreme options dropped
The president made clear he would not build up US forces into the hundreds of thousands.
He also ruled out reducing the campaign to a counterterrorism effort, which would involve a large scale withdrawal of troops and a focus on special operations forces operating in the Afghanistan-Pakistan region, senior aides said.
A recent report by McChrystal said the military mission risked failure unless more US troops were sent.
McChrystal is understood to be seeking between 30,000 and 40,000 more troops to be deployed, but some Obama administration officials have expressed concerns that too large a US military presence runs the risk of alienating the Afghan population.
Obama, who has already added 21,000 troops to the campaign - raising the total to 68,000 US troops by the end of the year - is under growing pressure from the US public and his political opponents over the war, which marks its eighth year on Wednesday.
Nearly 900 US soldiers have died in the war which was launched after the September 11, 2001, attacks on the US after Afghanistan's Taliban rulers were accused of sheltering al-Qaeda fighters and leaders.
And the number of fatalities this year - more than 230 - is already the highest in a year so far.
The White House said prior to Tuesday's meeting that Obama considered it "tremendously important" to listen to congress about the war but would not base his decision on the mood on Capitol Hill or waning public support for the war.
"The president is going to make a decision - popular or unpopular - based on what he thinks is in the best interests of the country," Robert Gibbs, his press secretary, said.
The president gave no timetable for a decision on troop numbers, which prompted a sharp exchange with John McCain, his Republican opponent in last year's election, according to officials at Tuesday's meeting.
Obama told the legislators he would show urgency but also be deliberate and decide on troop numbers only after settling on the strategy ahead.
Harry Reid, the Democratic senate majority leader, said Democrats and Republicans told Obama during the meeting that they would rally behind him whatever decision he made.
"The one thing that I think was interesting is that everyone, Democrats and Republicans, said, 'Whatever decision you make, we'll support it,' basically," Reid said.
But Mitch McConnell, the senior Republican in the senate, said: "I think Republicans will be able to make the decisions for themselves."
However, he said that a significant number of Republicans would back Obama's next move if he listened to his military commanders.
John Boehner, the House Republican leader, said he recognised that Obama had "a tough decision, and he wants ample time to make a good decision".
"Frankly, I support that, but we need to remember that every day that goes by, the troops that we do have there are in greater danger," Boehner said.
Mike Soraghan, a congressional correspondent for The Hill newspaper, told Al Jazeera that US politicians were beginning to "go to their corners and stake out positions" on Afghanistan.
"A lot of Democrats are coming out against this plan by McChrystal ... they are expressing strong doubts about it. [But] Republicans are very much supporting the idea of escalating the war," he said.
"If [Obama] is going to order 40,000 more troops, he will probably need Republican votes to sustain that. It would probably come down to a vote on funding [for the war] next year."