Peter Kuitenbrouwer enumerates the reasons why the violence this weekend was pretty much inevitable:

Prime Minister Stephen Harper has something to answer for tonight. It is hard for this writer to escape the feeling that this summit was designed with every possible star aligned for ugliness to occur. The summit is held on a summer weekend, after university and high school exams are over; all the students are out and free and have time on their hands. Summer weather is perfect for a march. The summit takes place in the heart of Toronto: everybody in Canada has a friend in Toronto where they can stay during a protest.

And can we not say that assembling the greatest number of police in one spot in the history of Canada, and spending more on fences and security than Canada has ever spent before, has a provocative effect?

Why didn’t they keep both summits in Huntsville? Or, as several people have pointed out, at a remote Canadian Forces base where air transport and physical security are already in place?

Update: Jonathan Kay thinks the media and the echo chamber of Twitter, Facebook, blogs, and instant messaging combine to make a few incidents appear far bigger and more scary than they really are:

This is one of those stories the social media has gotten wrong: a million tweeters all tweeting up the same three burning police cruisers and few dozen wrecked storefronts. The number of protestors wasn’t even that big (even if the media insists on calling the protests “massive.”) The estimate I’ve seen thrown around is about 10,000. To put that figure in perspective, the number of protestors who swarmed Quebec City at the Summit of the Americas in 2001 was approximately 100,000 — tens times as large.

[. . .]

As I approached the intersection of Queen and Spadina, I could see a rowdy crowd of several thousand gathered. There were a few earnest placards in evidence (“Mother earth convenes the G-6billion. Fuck the G20″). But mostly, it was just excited-looking teenagers surrounding the cop car, like hyenas around their kill. In that moment, it looked like things were about to get truly ugly. I began eying the stores lining Queen, trying to predict which one would get trashed first.

But then came the sirens, and the atmosphere changed very quickly. From down Queen Street, headed eastbound, a speeding convoy of unmarked white busses stopped outside the Silver Snail comic store, and out poured police in full riot gear — helmets, batons, body armor. From an accompanying black suburban came a few even more serious-looking fellows, including at least one with a military-style assault rifle. They never said a word, never issued a threat, never fired any of their crowd-control weapons. They just advanced, in a line, several officers deep, toward the heart of Spadina and Queen. There wasn’t any violence — at least none that I saw. The worst I witnessed was a single protestor who threw a bottle from amidst the anonymity of the crowd, which gained a few oohs and ahs after it fell harmlessly on the concrete.