Prime Minister Stephen Harper says he understands clear timelines are essential in getting Canada out of Afghanistan but won't accept the Liberal proposal to stop all combat by the Feb. 2009 end date.

Responding to demands from the Liberals to determine clear deadlines for the mission, Harper said Thursday he is unwilling to take control away from the military leaders on the ground, saying they best understand the reality of working in the dangerous Kandahar province.

"It isn't the role of politicians to dictate their mission," he said to jeers from the opposing side of the House of Commons.

Liberal Leader Stephane Dion replied:"It is up to politicians to establish clearly what the mission is."

Despite a refusal to cooperate with Liberal demands to move to a support and training role next year and set a firm 2011 end date for the mission, Harper continued to remind Parliament that the option being proposed by the Conservatives wasn't really that different.

"This government has indicated a wish to put an end to the mission in 2011," said Harper, although making no firm commitment to a withdrawal at that time.

"I realize the Liberal Party has said something that is different but more or less the same. We are seeking common ground. The Liberals and Conservatives.... must work together here."

As the clock ticks toward a series of confidence votes that could bring down the government in March, the Conservatives seemed increasingly interested in showing themselves as willing to cooperate.

Barring deals on the extension of the Afghanistan mission, the federal budget and an extensive Tory crime bill, the opposition parties could bring the government down, taking the country to the polls as soon as mid-April. 

However, the Liberals recently said they would support the extension of the Afghan mission until 2011 if Ottawa will notify NATO that it is pulling out at that time.

Harper has said leaving in 2011 would be the ideal situation but he's not sure it's a realistic goal at this time.