WASHINGTON - Flanked by the man who once declared the war in Afghanistan unwinnable, President Barack Obama said Thursday the U.S. has yet to decide on the best strategy for the ongoing conflict and won't send any more soldiers there until it does.

"We have lacked as clear of a strategy and a mission as is necessary in order to meet our overriding objective, which is to dismantle and disrupt and destroy al-Qaida," Obama said following an hour-long White House meeting with Prime Minister Stephen Harper.

The two leaders took questions in the storied Oval Office, where a wealth of historical treasures and ornate furnishings were barely visible beyond the crush of Canadian and American media who were crammed inside.

Keen to reflect a sense of ease and goodwill with a president who remains wildly popular in Canada, Harper went so far as to refer to Obama as "Barack" during his initial remarks. Obama appeared to take no offence, smiling broadly as Harper noted the fact they were conversing for the seventh time.

Amid all the health-care hand-wringing in the U.S. and protectionist panic in Canada, it was Obama's stark admissions about the American role in Afghanistan that commanded the most attention.

The original goal of the mission -- to seek out and destroy the forces behind the 9-11 attacks eight years ago -- is all but a distant memory, thanks in part to the absence of a clear course of action, Obama suggested.

The comments come amid a growing chorus of voices warning the war could shape up to be Obama's Vietnam. Congressional leaders are openly questioning the wisdom of increasing the American presence in Afghanistan.

Indeed, the U.S. earlier this year bolstered its Afghan ranks with 21,000 additional troops to help facilitate the presidential election -- an influx of U.S. resources hailed by Canadian forces as a godsend.

In March, Harper told CNN: "We are not going to ever defeat the insurgency ... my reading of Afghan history is that it is probably had an insurgency forever, of some kind."

Canada is scheduled to withdraw its troops from Afghanistan in 2011; Harper has said repeatedly that Afghanistan needs to develop and bolster its own security forces.

On Wednesday, he said it again.

"Whatever we and NATO and our UN allies are doing .... we make sure that eventually this country can stand on its own two feet, particularly on the security side."

America's top military officials want even more troops beyond the current level of 68,000. But Obama said their calls for a mightier military presence will not be heeded hastily.

"There is no immediate decision pending on resources, because one of the things I'm absolutely clear about is you have to get the strategy right and then make determinations about resources," he said.

"You don't make determinations about sending young men and women into battle without having absolute clarity about what the strategy is going to be."

The two leaders met at the White House for more than an hour, touching on a variety of subjects -- most notably the economy, the flow of energy between the two countries and the various trade "irritants" that have cropped up in the wake of the global economic meltdown.

With Harper facing the possibility -- albeit dwindling daily -- of an election this fall, the optics couldn't have been sweeter: a portrait of George Washington behind him, the prime minister sat in the most storied office in the world next to a president who enjoys unprecedented popularity in Canada.

Obama made a point of mentioning how persistent Harper had been on the "Buy American" provisions in the U.S. economic stimulus package.

"He's been on the job on this issue," Obama said.

Another particular sore spot has been an American policy to enforce restrictions on foreign charter flights that effectively prevent Canadian sports teams from visiting more than one American city before returning home. It appeared close to being resolved.

Harper said a preliminary agreement had been reached between Air Canada and the U.S. Department of Transportation to ease the restriction, which the carrier had assailed as unfair.

It was yet another irritant in a relationship that has been strained by an apparent rise in U.S. protectionism. Obama said Canada had "legitimate concerns" about "Buy American," but was quick to suggest once again that the threat has been overblown by America's trading partners.

Trade between the U.S. and Canada remains robust, he said.

"I'm glad to hear that Canadians see the recovery package as significant," said Obama, pointing out his own stimulus efforts have been criticized by his opponents.

But he noted that the American effort to breathe life into the U.S. economy was well within the confines of fair trade established by the World Trade Organization.

"These are legitimate issues that have to be raised, but on the overall scale of our trade relationship, these shouldn't be considered the dominant (issue)," he said.

"That doesn't mean they're not a source of irritation between the United States and Canada ... but there is no prospect of any budding trade wars between our two countries."

Harper is scheduled to meet Thursday with Senate Majority Leader Harry Reid (D-Nev.) and Senate Minority Leader Mitch McConnell (R-Ky.), as well as with Speaker Nancy Pelosi, before travelling to New York for a speech to the Canadian American Business Council.

Obama and Harper will see each other again next week at the two-day G20 summit in Pittsburgh, which gets under way Sept. 24.

Outside the White House, a handful of protesters were on hand Wednesday to denounce the production of so-called "dirty oil" from Canada's oilsands.

Not far away, outside the Canadian Embassy, protesters dressed in seal costumes stained with red paint were dragged off by police as part of an event to protest Canada's seal hunt.