Having just finished watching the NDP's Paul Dewar speak on the Afghanistan question, it only confirmed a "becoming obvious" point- the Liberals will be on the defensive until we demand a vote on the mission extension.
First off, the Liberals have supported this type of mission for months, there is no philosophical alteration. If anything, this whole process is merely the Conservatives coming to the Liberal way of thinking, moving forward. In that sense, one can understand why the Conservatives developed this extension math, because they foresaw broader support for the concept. In addition, in the most simplistic fashion, one can also follow the logic that would see the Liberals giving approving "cues", again because the idea is nothing foreign to on the record, stated Liberal policy. However, and this is the key point, none of these facts, the chronology, really matters, because it is this lack of a VOTE that casts a massive shadow over the entire affair.
Until the Liberals agree to a vote, then they might as well resign themselves to giving the NDP carte blanche to pound the snot out of us, make us look like co-conspirators, usurping democratic will, blah, blah, blah. The Conservatives "broke their promise" to consult Parliament, and by arguing the finer details of Parliamentary protocols, the Liberals allow themselves to get lumped in and opponents have a free ride. The NDP doesn't make sense on Afghanistan, in many respects, but by not holding the government to full and formal account, it's no matter, they are allowed to go on pure and effective offence. Fair? Whatever. Right or wrong? Who cares. Bottom line? We'll lose the argument, because we lack the soundbite position, we are lost in the detail, while others react with powerful indignation.
IMHO, it's vote or bust for the Liberals. Forget about the "system", what government's can or can't do, it is not the Liberals job to educate us all on Parliamentary precedent. The Liberals are running around the country telling us all "you can't trust these guys", a persuasive narrative, rife with easily understood examples, and yet we don't take this Afghan debate to the most transparent conclusion. It's not to say a vote guarantees anything, but a vote says to Canadians "here's what we will support" and if it strays from those voted on parameters, then the government is offside. A vote still allows the NDP to protest the position, but all of the behind closed doors stuff, the guilty by association, broken promise routine, is neutered. No matter the semantics, you will forever lose the public relations battle, when your position refuses to bring a matter this important before the elected Parliaments, the optics NEVER work.