You've got to be aware of the possible consequences of your actions, that's true enough. Challenging the system involves taking risks, and there's a duty to do your best to ensure that those risks are carried by people who understand them and accept them.

And there's an element of provocation in many, perhaps most demonstations, including the most non-violent. Sticking a flower in the barrel of a soldier is for some soldiers a very provocative thing to do.

The thing with Kent though was that the action of the "National Guard" was not something that had precedents. All right there may have been examples in American history where the National Guard had shot down striking workers, or black people - but white middle-class teenage students? Noone could have expected that, any more than anybody could have expected the Paras on Bloody Sunday to be allowed to murder 14 unarmed people in Derry a couple of years later.