As Heric points out - people prefer inertia to action. But in regarding circumstance as being the primary motivating factor he neglects to say that public opinion freely formed is what drives circumstance.
But public opinion is fickle depending on how and by whom it is formed.
One thing for sure though - when Govt's try to tell you what your opinion should be - and in this I do mean Bush+Blair, though all govt's to some extent will be the same - public opinion does change - fast. If in line with Govt. then fine for change, but sometimes it's the govt. policy that public opinion is hardened against.
And that's called unpatriotic....?
Now where was I going with this.......