Every. Single. One. I've met —and I used to be very active politically, often in tandem with Veterans for Peace.
While, at first glance, this may imply a certain bias, but my consecutive experience of that test pool's scope and yet congruent views on war at every level surprised me. And, it's not even just a "yea" to a vote, each one had nuanced influences behind their view.
To the point, that was during Desert Shield, and I've solo traveled the world for months at a time in the years between —yet, I've still not met (or even heard a friend mention) a pro-war vet in over 35 years.
/my2¢