Using such a safe zone to nurture a “moderate” rebel force would also require American ground troops, since someone would have to decide which of Syria’s myriad rebel groups to shelter and which to forcibly expel. The United States might outsource that work to Arab, Turkish, or Kurdish allies, but these allies wouldn’t necessarily choose the same rebels, fighting for the same agenda, as America would.

So to make a safe zone effective, even if Russia weren’t in Syria, you’d need lots of American troops. Had the debate moderators confronted the GOP contenders with this reality on Tuesday, it would have quickly deflated their bravado, since post-George W. Bush Republican foreign policy rests on the premise that the United States can restore order and hegemony in the Middle East without the sacrifice of American lives.

But if a no-fly zone—which, sadly, Hillary Clinton supports too—was dubious before Russia’s intervention, it’s even more dubious now. As Mueller notes, the more such a zone strengthened the non-ISIS rebels seeking to overthrow Syrian President Bashar al-Assad, the more Russia would likely escalate its attacks on those rebels, thus neutralizing whatever benefit America’s intervention provided, while increasing the chances of a military confrontation between Washington and Moscow.

For many in the GOP field, this prospect is an occasion for swagger. “My first phone call would be to Vladimir,” declared Chris Christie last month, “and I’d say to him, ‘Listen, we’re enforcing this no-fly zone. And I mean we’re enforcing it against anyone, including you. So don’t try me. Don’t try me. ‘Cause I’ll do it.’”

This might prompt a reasonable person to ask whether America’s commitment to Syria’s “moderate” rebels is important enough to risk World War III over. After all, those moderates are extremely weak. And in part because of that weakness, some have forged alliances with jihadist groups that, while not ISIS, are at least as hostile to liberal democracy and to the United States as Bashar al-Assad is. The chances that Syria’s moderate rebels could defeat Assad, defeat ISIS, rid themselves of their al-Qaeda-like allies, and create a stable, decent Syria are vanishingly slim.

But for the hawks in the GOP field, this is almost beside the point. The point is to show that America still runs the Middle East. Thus, the fact that Russia is now bombing Syria is not a reason to stay out; it’s a reason to go in.

If this sounds vaguely familiar, it should. It’s a return to the worst mindlessness of the Cold War. In the second half of the last century, the United States sent large quantities of arms into poor countries like Angola, Somalia, and Nicaragua, which posed no serious threat to the United States, to fund rebels and regimes with extremely dubious human-rights records—all to keep those countries out of Russia’s hands. Instead of determining which parts of the world were strategically important enough to the United States to be worth expending blood and treasure for, as the diplomat George Kennan urged, the U.S. decided that preventing Soviet influence was an interest in and of itself. This logic led President Lyndon Johnson to send hundreds of thousands of troops to Vietnam, fueling a war in which millions died, not because almost anybody in his administration thought South Vietnam mattered in and of itself, but because letting it go communist would undermine America’s credibility in Asia and the world.