The Brookings Institute asks “End the War in Syria? How? When?”

“The beginning of wisdom,” a Chinese saying goes, “is to call things by their right names.” And the right name for what is happening in Syria — and has been for more than a year — is an all-out civil war.

Syria is Lebanon of the 1970s and ’80s. It is Afghanistan, Congo or the Balkans of the 1990s. It is Iraq of 2005-2007. It is not an insurgency. It is not a rebellion. It is not Yemen. It is certainly not Egypt or Tunisia.

It is important to accept this simple fact, because civil wars — especially ethno-sectarian civil wars such as the one burning in Syria — both reflect and unleash powerful forces that constrain what can be done about them. These forces can’t be turned off or ignored; they must be dealt with directly if there is to be any chance of ending the conflict.

So, how do these kinds of wars end? Usually, in one of two ways: One side wins, typically in murderous fashion, or a third party intervenes with enough force to snuff out the fighting. Until Washington commits to either helping one side or leading an intervention in Syria, nothing else we do will make much difference. The history of civil wars — and of efforts to stop them — demonstrates what is likely to work and what is likely to fail.

At the top of the list of initiatives that rarely succeed in ending a civil war on their own is a negotiated settlement. The likelihood that this could work without force to impose or guarantee an accord is slight. It’s why Kofi Annan’s mission as the U.N.-Arab League envoy was always likely to fail and why, now that Annan has announced his resignation, the effort should be cast aside as a distraction.

It’s also why the Obama administration’s fixation on Russia’s supposed leverage with the Syrian regime and the idea of a Yemen-style solution in which President Bashar al-Assad steps down are equally misconceived. Assad is unlikely to step down, because — like Radovan Karadzic, Saddam Hussein, Moammar Gaddafi and many others before him — he believes that his adversaries will kill him and his family if he does. And he is probably right.

Even if he did voluntarily leave office, his resignation or flight from Syria would probably be meaningless: The war is being led by Assad, but it is being waged by the country’s Alawite community and other minorities, who believe that they are fighting not just for their privileged place in Syrian society but for their lives. Were Assad to resign or flee, the most likely outcome would be for another Alawite leader to take his place and continue the fight.

The insistence that “Assad’s days are numbered” is not only probably incorrect, it is largely irrelevant. Throughout the Lebanese civil war of 1975-1991, there was always a man sitting in the Baabda Palace calling himself the president. And he had a military force that reported to him called the Lebanese Armed Forces. In truth, he was nothing more than a Maronite Christian warlord, and the remnants of the Lebanese Armed Forces had become nothing but a Maronite militia, yet the names persisted.

So Assad may not fall for some time, and he may continue to call himself the president of Syria. He may even be able to sit in an embattled Damascus, defended by a military formation still calling itself the Syrian Armed Forces. But that won’t make him anything more than the chief of a largely Alawite militia.

The dangers of picking winners

If the United States decides that it is in its interest to end the Syrian civil war, Washington could certainly decide to help one side win.

In effect, we’ve already done so. Not only has the Obama administration demanded that the Assad regime relinquish power, but numerous media reports say that the United States is providing limited covert support to the Syrian opposition. According to these reports, the aid is nonlethal — helping to vet fighters, providing some planning guidance.

What Washington has not done is give the opposition the kind of help that would allow it to prevail in short order. Right now, the standoff in Syria is about guns against numbers. The regime has a small pool of tanks, artillery, attack helicopters and other heavy weapons that allows it to beat back the opposition wherever such forces are committed. So whenever the opposition threatens something of great importance to Assad’s government — such as Damascus or Aleppo — the regime can stymie the attack. But the opposition’s numbers are growing, allowing it to take control of large swaths of territory that is of low priority to Assad.

Over time, and especially if its supply of replacements and spare parts from Iran and Russia can be choked off, the government’s stockpile of heavy weapons will diminish, and as the war becomes a contest of light infantry on both sides, the numbers of the opposition should begin to tip the balance.

The problem is that helping the opposition “win” might end up looking something like Afghanistan in 2001. Opposition forces may end up in control of most of the country, even Damascus, but the Alawites and their allies might be holed up in the mountains, continuing the fight. And as in Afghanistan, where the Northern Alliance held the Panjshir valleyfor years against the otherwise overwhelming force of the Taliban, so too might the Alawites be able to hold their mountainous homeland along Syria’s western coast for a long time.

The parallels are plentiful. The Syrian opposition is badly fragmented, with divisions within and between the political groups and fighting forces. In Afghanistan, after the Soviet departure in 1989, a similar situation was a recipe for internecine warfare. Indeed, the various mujaheddin groups fell to fighting one another even before the Soviet puppet regime of President Najibullah fell —allowing the regime to survive until the Taliban crushed Najibullah and the mujaheddin alike.

In Syria, the dominant force that might emerge from an opposition takeover could be the Syrian Muslim Brotherhood. The group, living for decades under persecution from the Shiite-dominated Syrian Baath Party, is a very different creature from the Brotherhood parties that have taken power in Egypt and Tunisia. It is an old, unreconstructed, hard-line, sectarian version — more like the Taliban.

For all of these reasons, an opposition victory could mean trading one regime of persecution and slaughter for another. All of this needs to be factored into any U.S. discussion of whether to help the rebels prevail.

If Washington does choose to intervene, however, there are ways to reduce these risks. First, America could start providing lethal assistance, particularly more advanced anti-tank and anti-aircraft weapons to help kill off the regime’s heavy weapons faster and allow the opposition to prevail more quickly.

Even more important, the United States and its NATO allies could begin to provide military training for Syrian fighters. More competent opposition forces could better meet and defeat government troops. Such training would also help diminish the factionalism among the armed groups and bring greater discipline to the opposition, including in a postwar environment. Indeed, the American program to organize and train a Croatian (and Bosnian Muslim) army in the mid-1990s was crucial both to military victory in the Bosnian civil war and to fostering stability after the fighting.

Moreover, one of the best ways for the United States to influence a post-civil-war political process is to maximize its role in building the military that wins the war.

Ending a war vs. building a nation

Historically, the only real alternative to ending a civil war by picking a winner is for an outside force to suppress the warring groups and then build a stable political process that keeps the war from resuming. The military piece of this — shutting down the fighting — is relatively easy, as long as the intervening nation is willing to bring enough force and use the right tactics. The hard part is having the patience to build a new, functional political system. The Syrians in Lebanon, NATO in Bosnia, the Australians in East Timor and the Americans in Iraq demonstrate the possibilities and the pitfalls.

This course is typically the only way to end the violence without the mass slaughter of the losing side. It also can prevent fragmentation and an outbreak of fighting among the victors. If done right, it can even pave the way toward real democracy (as the United States started to do in Iraq before its withdrawal last year), which results in greater stability in the long run.

But it is not cheap, and it requires a long-term commitment of military force and political and economic assistance. The cost can be mitigated in a multilateral intervention such as in Bosnia and Kosovo, rather than a largely unilateral effort along the lines of the U.S. reconstructions of Iraq and Afghanistan. In the case of Syria, that means the United States isn’t the only nation that needs to sign on; Turkish, European and Arab support matter as well.

Right now, there is absolutely no appetite in the United States for a Bosnia-style intervention in Syria. That is understandable. Unlike in Libya, the humanitarian disasters unfolding in Syria have not been enough to galvanize the United States to action. In addition, there is nothing intrinsically important there for U.S. vital interests. Syria does not have significant oil reserves, nor is it a major trading partner. It is not an ally and was never a democracy. If Syria were merely to self-immolate, it would be a tragedy for the Syrian people but extraneous to American interests.

However, if Syria’s civil war spills over into the rest of the Middle East, U.S. interests would be threatened. Civil wars often spread — through the flow of refu­gees, the spread of terrorism, the radicalization of neighboring populations, and the intervention and opportunism of neighboring powers — and Syria has all the hallmarks of a particularly bad case.

At its worst, spillover from a civil war in one country can cause a civil war in another or can metastasize into a regional war. Sectarian violence is already spreading from Syria; Iraq, Lebanon and Jordan are all fragile states susceptible to civil war, even without the risk of contagion. Turkey and Iran are mucking around in Syria, supporting different sides and demanding that others stop doing the same. Terrorism or increasing Iranian influence might pull even a reluctant Israel into the fray — just as terrorism and increasing Syrian dominance pulled Israel into the Lebanese civil war years ago.

This is what we must watch for. Spillover may force Washington to contemplate real solutions to the Syrian conflict, rather than indulge in frivolous sideshows. If that day comes, our choice will almost certainly be between picking a winner and leading a multilateral intervention.

Chances are we will start with the former, and if that fails to produce results, we will shift to the latter. That may seem far-fetched, but it is worth remembering that in 1991 there was virtually no one in the United States who supported an American-led multilateral intervention in Bosnia, and by 1995 the United States (under a Democratic administration) was doing just that.

Thanks to BROOKINGS Institute, Washington