Premature Anti-Bushite
Paul Krugman observes that "Even now, it’s better for your reputation not to have noticed until, say, 2005 that we had some dangerous people running the country. If you noticed earlier — or, worse yet, you caught on to the administration’s essential mendacity right from the beginning — it’s not a sign that maybe you had good judgment. It shows that you were an irrational Bush hater."
Indeed, a bit like the concept of the premature anti-fascist it's considered a bit disreputable to have been too right, too early on. After all, the "logic" seems to go, a dogmatic pacificist would have been opposed to invading Iraq from the get-go, and dogmatic pacifism is wrong, "therefore" early opposition to the war is probably a sign of unsound views. It's absurd and it's a problem.
I'll note that in politico-media terms, I think this would be an underrated reason to welcome a Barack Obama Administration. His ascendancy would, as such, end the marginalization of early war opponents by bringing a bunch of them -- including himself -- into top positions. A Hillary Clinton Administration, by contrast, even if it governs extremely effectively will also serve to perpetuate the idea that the smart money is always on war irrespective of the circumstances.