This post from BuckeyeShadow reminded me of something I read on NPR the other day:
Instead, Heaney continued, "attendance at anti-war rallies declined precipitously and financial resources available to the movement have dissipated. The election of Obama appeared to be a demobilizing force on the anti-war movement, even in the face of his pro-war decisions."
Instead of saying Republicans "alienate, spite and/or malign" the anti-war movement, it seems they cause it to exist.
Democrats pursue effectively the same strategy of foreign military intervention, claiming American exceptionalism, etc. of the Republicans yet public protests dwindle.
In other words, the American anti-war movement seems less anti-war than it does anti-republican.