Read more of Slate’s coverage of the Libyan protests.

It’s a no-brainer that President Barack Obama should do something to help the Libyan protesters bring down the monstrous regime of Muammar Qaddafi. The tough question is what.

To elaborate on this point: What actions would help, what actions might hurt, and, perhaps most important, what actions can be effectively sustained? Qaddafi, after all, has hung on to power for 42 years; he might not tumble with one quick push.

The U.N. Security Council is about to meet as I write this. It will no doubt issue some grave condemnation, just as, earlier today, the Arab League expelled Libya from its membership roster and Secretary of State Hillary Clinton called on Qaddafi to “stop this unacceptable bloodshed.”

All this is fine and necessary, but by this point Qaddafi is impervious to shame. His endless rant on Libyan state television today—shouting, looking disheveled and a bit insane, denouncing the protesters as naive youth drugged by American imperialists, and threatening to kill them all if the disorder continues—is proof of that.

Sen. John Kerry, the Massachusetts Democrat who has been acting like a secretary-of-state-in-waiting for a while now, proposed a few tangible actions. Foreign oil companies in Libya should suspend operations until the violence stops; U.S. sanctions, which George W. Bush dropped when Qaddafi dismantled his nuclear program, should be resumed; Libya’s military officers should be warned that, if they keep shooting and strafing their citizens, they’ll be prosecuted for war crimes after Qaddafi falls; and, meanwhile, the United Nations should remove Libya from its seat on the Human Rights Council (a shameful joke to begin with).

These are all excellent ideas, which the proper authorities and CEOs could and should make good on with a finger snap. But what about more forceful measures?

Some commentators have advocated imposing a “no-fly zone” over Libya, to prevent Qaddafi’s pilots from continuing to bomb and strafe demonstrators, as several eyewitnesses have reported they’ve done.

Presumably this zone would be enforced by U.S. or NATO combat planes. It’s a feasible idea. The cease-fire at the end of the 1991 Gulf War imposed a no-fly zone over Iraq, and it was maintained for the entire 12 years until Saddam Hussein’s ouster—through, and despite, many Iraqi attempts (all unsuccessful) to shoot down the planes.

But if any leaders sent air power over Libya, they would first have to calculate how far they’d be willing to go. Would they bomb Libya’s airfields? If Qaddafi stopped strafing the crowds and sent tanks against them instead, would they bomb the tanks? And if that didn’t halt the oppression, would they send in ground troops? (By any measure, this last step would probably be a very bad idea.)

Such considerations may be why Egypt’s U.N. ambassador told reporters this morning that the Security Council was unlikely to put a no-fly zone on the agenda. If that’s the case, should Obama, or a U.S.-NATO alliance, impose one by themselves?

In his TV speech today, Qaddafi declared that the demonstrations against him are the latest episodes of an imperialist plot that began with President Ronald Reagan’s bombing campaign in the mid-1980s. It seems doubtful that many viewers believed him, but who knows?

Some might argue that such concerns are irrelevant. But it’s worth noting that Operation Desert Storm, the 1991 Gulf War that pushed Saddam’s troops out of Kuwait (and imposed the sanctions and no-fly zone that followed), succeeded in good part because it really was a coalition campaign that involved every Arab and Muslim nation in the region—and not just in name. Egypt, Syria, Saudi Arabia, even Libya sent whole armored divisions or air wings. They didn’t affect much militarily, but they were tremendously important politically. Their presence ensured that no one would see the war, either during the fighting or after, as merely a Western power ploy, a colonial grab for oil.

Whatever actions Obama or anyone else might take in Libya, it’s important to take similar precautions.

On one level, this may not seem so difficult. Qaddafi, who once touted himself as the dashing would-be leader of Pan-Arab adventurism, is now reviled and rejected publicly by the Arab League. (The only leaders rushing to embrace him in his darkest hour are anti-American socialists half a world away: Fidel Castro, Daniel Ortega, and Hugo Chavez, of Cuba, Nicaragua, and Venezuela, respectively.)

On another level, though, it’s unclear how far the Arab leaders might be willing to go down this road. They must be asking themselves: Would helping to get rid of this pest show their people, and the rest of the world, that they’re not congenitally averse to popular revolts—or would it only intensify the domestic pressures on their own regimes to step down?

Even if Obama wanted to take unilateral action, his options are limited. Contrary to Qaddafi’s ravings about plots by American agents, U.S. leverage in Libya is almost nonexistent: a barebones embassy, scant contact with the military, and economic aid of just a few million dollars a year, most of it to assist with Libya’s disarmament program.

This could change. I have no idea (and doubt if anyone on the outside does) whether the United States, or any other Western nation, has established contact, much less opened lines of cooperation, with the Libyan military officers and diplomats who have defected from Qaddafi’s regime. If so, they would have to be kept extremely secret, given Qaddafi’s charge that the West is engineering the revolt.

If outsiders are needed to push him out of power, Great Britain and Russia may be the ones to take the lead, as they have far more extensive commercial interests in Libya.

Britain sold Libya more than $6 million in ammunition, including riot-control ammo, in the third quarter of 2010 alone—a chapter in shame that Prime Minister David Cameron (who recently flew to Egypt to strike a relationship with the nascent regime there) might wish to rectify.

More tangibly, in 2007, BP signed a $900 million deal with Libya to dig 17 exploratory wells across an area 10 times the size of BP’s quite extensive operations in the Gulf of Mexico.

Just a year ago, Russia signed a deal to sell $1.8 billion in arms to Libya—this on top of multibillion-dollar contracts, signed in 2008, to build a railway line and assist in energy production.

BP and the Russian government announced on Monday that they were taking all their workers out of the country—a move that they, and perhaps some interested parties in Libya, would like to see reversed in the near future.

In other words, there are many forces out there, private and public, with mutual and overlapping interests in seeing Qaddafi go soon.

Their wishes may come true, judging from reports that opposition rebels have essentially taken over the eastern part of the country, even hoisting the flag of pre-Qaddafi Libya, and luring at least some of the military units garrisoned there to join their side of the struggle.

Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, emphasized in an interview today on Al Jazeera, “The events in each country”—Tunisia, Egypt, Bahrain, and now Libya—”have been up to the people in that country.” The United States, he said, would be happy “to see how we can support this kind of change in a way that is meaningful, but,” he added, “it is up to the people of the country to make the decisions about their own future.”

Let’s hope that we are already engaged in seeing how we can support this kind of change, as Mullen delicately put it—and that we’re working in coalition with other interested parties in the region and beyond.

Let’s also hope that, after Qaddafi falls, whatever we may or may not be doing now, Congress will get over its customary suspicion of foreign aid and pony up billions of dollars—and not just for Libya. It costs money to help nurture the civil institutions without which popular protests degenerate into anarchy or boomerang into dictatorship. But it’s worth more to national security than any number of billions of dollars spent on nuclear submarines or aircraft carriers.

Libya in the time of Qaddafi’s twilight poses one of those rare opportunities when America’s interests and ideals really do coincide. It would be a shame to let it pass by.

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