During the post-World War II period, opposition to U.S. militarism and involvement in dubious military conflicts has usually been stronger on the political left than the right. Left-wing, anti-war sentiment reached its peak during the Vietnam War, when groups opposed to that conflict could sometimes mobilize tens of thousands of demonstrators. Opposition to subsequent U.S. military crusades was less robust, but even as late as the Iraq War, there were sizable anti-war demonstrations in the streets.
There have been warning signs for some time, though, that opposition to unnecessary armed conflicts has lost its appeal to much of the political left. For one thing, there was always a partisan bias to anti-war movements. Even during the heyday of resistance to the Vietnam War, the criticism became more intense after Republican Richard Nixon took over the White House than it had been when Democrat Lyndon Johnson occupied the Oval Office. The bias was even more apparent in later decades. There was far more criticism of Republican George H.W. Bush’s Persian Gulf War than there was of Democrat Bill Clinton’s wars in Bosnia and Kosovo. Indeed, a distressing number of prominent liberals found reasons to praise Clinton’s military crusades in the Balkans.
The partisan factor has grown even more intense in the twenty-first century. Left-wing groups mounted a fairly serious effort to thwart Republican George W. Bush’s invasion of Iraq. But when Democrat Barack Obama greatly escalated U.S. military involvement in Afghanistan and led a NATO assault to remove Libya’s Muammar Qaddafi from power, the reaction was very different. Except for a few hard-left organizations, such as Code Pink, the sounds coming from the usual supposed anti-war liberal quarters were those of crickets. Likewise, there has been little push-back to Obama’s gradual return of the U.S. military presence in Iraq or the entanglement of the U.S. military in Syria.