That's a tough one.
I don't really like having it that this is peace while this is war, with a clear line between the two. It's a continuum; at various points along it, you're rather more at war or rather more at peace.
Is Canada at war on the scale of what it was in Korea? I don't think so, but there are definitely aspects of what's going on in Afghanistan that could be considered war.
Pakistan has played a critical and very important role in much of the trouble of the last few decades. I don't believe Afghanistan will be at war with itself, with Pakistan, or with its neighbours forever. I think we can come to terms, but it's a very difficult, very complex situation.
Is Canada at war globally? No, but we sure as hell are close to it on the continuum.
If Canada leaves, what happens? I don't believe the Afghan government today can stand on its own feet. Here is just one number to fathom this reality: about 58% of the Government of Afghanistan's budget is coming from foreign donors. If you cut 58% of your income, cut your foreign troops, and so on, Afghanistan is going to fall back into civil war. In the long term there are definitely going to be problems that will be exported to the region and possibly to the entire world.