For many conservatives, unfortunately, this is more or less correct. However, progressives have once again airbrushed their own past, which is about as anti-war as, well, war.
Much of this perception is relatively recent and primarily boils down to the Iraq War. The neoconservative warmongering was in full swing and for his part, Barack Obama gave a rather pleasant speech about his opposition to the war before it began. In his book, Obama elaborated,
What I sensed, though, was that the threat Saddam posed was not imminent, the Administration's rationales for war were flimsy and ideologically driven, and the war in Afghanistan was far from complete.
Not terribly bad, at least for a politician.