In a sense, Democrats did emerge as the de facto anti-war party during the Iraq war, but that was only because a Republican—George W. Bush—was commander-in-chief. And what of the Democrats who voted for the war and continued to fund it? Out of 77 senators who supported the resolution authorizing military force against Iraq in 2002, 20 are still in office and roughly half are Democrats, while out of the 296 votes in favor in the House, 90 are still in office and 57 of them are Democrats. Some of them, like Harry Reid and Chuck Schumer, went on to become party leaders. Two others, John Kerry and Hillary Clinton, went on to become secretaries of state and their party’s nominees for president in 2004 and 2016 respectively. All went on to support new military interventions and regime changes, albeit under a new, liberal interventionist, Democratic banner.
Conversely, steadfast non-interventionist Democrat Dennis Kucinich, who voted against the resolution, failed badly in both his 2004 and 2008 attempts at his party’s presidential nomination. Bottom line: Support for the war was hardly a deal-breaker for voters, any more than opposition to it was a dealmaker.
Reaction to war is just a microcosm of the political landscape, a manifestation of partisan-driven, short-term memory. Sure there might have been momentary disapproval, but when it came time to decide whether supporters of the war stayed or went, the sins of one’s party leaders meant very little in the zero-sum game of electoral politics. Parties outside the duopoly be damned.