OTTAWA - NDP Leader Jack Layton says the Taliban cannot be defeated by international troops and there's no point continuing to fight an unwinnable war in Afghanistan.

Although his party has long called for a withdrawal of Canadian troops, Layton's emphatic statement about the futility of the mission comes amid a new push to present his party as the sole anti-war option.

He intends to meet with Liberal Leader Stephane Dion next Monday and has a bleak message for him.

"It's an endless mission. There's no end in sight. We say it's a dead end,'' Layton told reporters Thursday.

"No one has laid out, anywhere, that it's possible to ultimately win a war in this region.

"No one. And historical experience shows that it's been impossible -- whether it be Alexander the Great, the British in the 19th century, or the Russians in the 20th century.

"We're saying let's recognize these historical realities.''

The NDP distributed a list of quotes from military officers, analysts, and former diplomat-turned-author Rory Stewart to support their case about the slim chance of defeating Afghan insurgents through battle.

And numerous observers including Canada's own Manley panel have noted that insurgent attacks have actually increased -- not diminished -- since foreign troops wrested control from the Taliban seven years ago.

But the historical portrait Layton paints is far fuzzier in reality.

The British did in fact defeat an Afghan insurgency in the Second Afghan War in 1880 -- and the battle ended in Kandahar, where Canadian troops are currently located.

And Alexander's trek through Asia did not stall in Afghanistan.

It ended in India, after his troops had already marched through Afghanistan and founded the cities of Herat and Kandahar. The latter was named after him.

Layton's remarks drew scorn from some military experts.

A British ex-special forces officer who fought alongside the mujahedeen in the 1980s and now runs a security company called the comments erroneous. Alan Bell also called them unhelpful to the Afghan government, and to the morale of Canadian soldiers and their families.

And Canadian military analyst John Thompson added: "I don't talk about social policy. (Layton) shouldn't talk about military history or strategy. I don't know much about social policy, and it's clear he doesn't know much about military history or strategy.''

The result of Monday's Layton-Dion discussion could carry major implications for the mission and for Canadian politics.

If Dion agrees with Layton, the three opposition parties could outvote the government in any parliamentary move to extend the Afghan mission beyond February 2009.

Such a move could split the Liberal caucus and pit its hawks and doves against each other -- which would provide an added bonus to Layton and a silver lining to Prime Minister Stephen Harper.

But if Dion, as expected, seeks a less stringent position than Layton, the NDP would surely cast itself as the sole proponent of peace.

That message would be aimed squarely at the left-leaning voters that the Liberals and NDP are battling for, and Layton was already testing it Thursday.

"I'm very concerned that Mr. Dion may be considering supporting the direction of Mr. Harper,'' Layton said.

Dion appears to be preparing a middle-ground message -- positioned somewhere between the NDP's call for a quick pullout and the government's desire for an extended combat mission.

Dion said that the Canadian Forces must respect their commitment to continue fighting until February 2009, and suggested they could remain beyond then in some limited capacity.

"I hope I will convince (Layton) to change his mind. Canada cannot pull out of Afghanistan all of a sudden, overnight,'' Dion said.

"We have an international commitment until February 2009 for the combat mission.''

Beyond then, he says Canadian troops can maintain a military presence to defend construction projects and provide training to Afghan soldiers.

He has not explained how that non-combat training could work, and a report by a panel headed by Liberal stalwart John Manley has suggested it could not.

The government has already said it supports the Manley report, the Bloc Quebecois and NDP oppose it, and the Liberals have not yet offered a clear position.

The opposition parties rejected a government motion to debate the Manley report at a parliamentary committee.

When Layton was asked why, he said the matter should be discussed in the House of Commons and not in committees where the prime minister and other party leaders do not sit.

The Afghan conflict was raised repeatedly in the Commons on Thursday and Prime Minister Stephen Harper was in the thick of the debate.

With controversy swirling over Canada's handling of detainees, he suggested Canadian troops could allow their Afghan colleagues to take prisoners on the field.

Such a move could technically allow Canada to avoid violating the Geneva Conventions which forbid transferring prisoners to countries that practice torture.

But human-rights groups oppose such a policy on the grounds that Canada could still be complicit in violations of international law.

Harper did not deny a report that Afghan army trainees are taking captives while battling alongside Canadian troops.

"As we train the Afghan forces to take over more and more of the responsibility for their security operations, of course they will be taking over more and more responsibility for these aspects of the security operation,'' he said.