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.

Some on the left hoped that the campaign of Senator Bernie Sanders for the Democratic Party’s presidential nomination signaled a revitalization of opposition to the warfare state among progressives. That did not prove to be the case. Foreign policy in general, and opposition to Washington’s wars in particular, was a secondary and anemic theme in his campaign against Hillary Clinton.

And Sanders may now have sounded the death knell for the liberal anti-war movement. Just days after Donald Trump’s upset victory in the 2016 presidential election, Sanders published a high-profile article in the New York Times outlining the policy agenda for progressives going forward. The piece contained the usual laundry list of identity politics and spending proposals that left-wing types have been pushing for decades. What was striking, though, is that the article contained not a single word—not a single word—about foreign policy. The United States is mired in the longest war in its history in Afghanistan, it has returned to the scene of its last major interventionist disaster in Iraq, and it is already entangled to a dangerous degree in Syria. The president-elect has indicated that he may tear up the agreement with Iran, wants to adopt a confrontational trade policy toward China, and wants to pour even more money into the Pentagon.

Yet the most visible and prominent political figure on the left apparently deems all of this unworthy of a comment in America’s most prestigious newspaper. That omission suggests that Sanders may believe his followers do not consider foreign policy very important. That would be worrisome. The other possibility is even worse: that he believes they have accommodated themselves to the warfare state—that as long as they can get the funding for their pet domestic programs, they are willing to back even more generous funding of the Pentagon and other elements of the national security apparatus. Such an assumption would also suggest that they would remain largely mute as Washington embarks on future military crusades. 

If the latter scenario proves true, we are witnessing the demise of anti-war liberals. It would then be up to libertarians and limited government conservatives to redouble their efforts to wage campaigns for peace, despite knowing that we may have few, if any allies, on our left flank.