Top government officials and ordinary newspaper pundits are debating whether the U.S. and its allies should intervene militarily against Moammar Gadhafi, perhaps by establishing a no-fly zone. This is the wrong question. The right question is: What happens if Gadhafi holds on?

That possibility no longer seems remote, as the colonel and his loyalists keep a firm grip on Tripoli and start inflicting military reversals on the rebels. A society as brutalized as Libya's will retain a powerful fear of its dictator even in his hour of weakness. Many Libyans will recall how Saddam Hussein crushed the Kurdish and Shiite uprisings of March 1991. They will recall, too, that the first Bush administration—which included then-deputy national security adviser and current no-fly zone skeptic Bob Gates—stood aside as Saddam viciously struck back.

What happened next is one of the darkest chapters of recent memory. An estimated 60,000 Iraqis, perhaps more, were killed in the revolt. Two million fled the country. The Iraqi people had to endure another dozen years under Saddam. The U.S. spent billions enforcing a no-fly zone that was a case of too little, too late. The war that ultimately toppled Saddam's regime exacted another huge toll in lives, including those of more than 4,000 Americans.

Looking back, it's worth noting that all of this may have been avoided if only the U.S. had forbidden Saddam from flying his helicopter gunships, which proved decisive in turning the tide of revolt. So why won't President Obama run the comparatively minor risk of doing similarly in Libya? Does he think he needs the U.N.'s permission? Sadly, he probably does.