Washington ? The U.S. and its allies are moving in Syria toward a program of covert support for the rebels that, for better or worse, looks very much like what America and its friends did in Afghanistan in the 1980s.

The parallels are spooky, if you’ll forgive the pun. In Syria, as in Afghanistan, CIA officers are operating at the borders (in this case mostly in Jordan and Turkey) helping Sunni insurgents improve their command and control, plus other activities. Weapons are coming from third parties (in Afghanistan, they came mostly from China and Egypt; in Syria, they’re mainly bought on the black market). And finally, a major financier for both insurgencies has been Saudi Arabia.

There’s even a colorful figure who links the two campaigns: Prince Bandar bin Sultan, who as Saudi ambassador to Washington in the 1980s worked to finance and support the CIA in Afghanistan and who now, as chief of Saudi intelligence, is encouraging operations in Syria.  

What does this historical comparison suggest? On the positive side, the Afghan mujahedeen won their war and eventually ousted the Russian-backed government. (Yes, that’s another eerie parallel.) On the negative, this CIA-backed victory opened the way for decades of chaos and jihadist extremism that are still menacing Afghanistan, its neighbors and even the United States.

The Obama administration, to its credit, recognizes the dangers ahead. That’s one reason Obama’s approach to this war has been cautious and, according to critics, half-hearted and ineffective. Because the way forward is so uncertain, the administration has been taking baby steps. But it’s the nature of these wars that a little involvement leads to more, and still more.

What does history teach us about such interventions that may be useful in the Syrian case? Here are several points to keep in mind as the covert war against Syrian President Bashar al-Assad ripens:

l The U.S. should be wary of supporting a Saudi strategy that inevitably is self-interested. The Saudis understandably would prefer that Sunnis who oppose autocratic rule should wage their fight far from the kingdom; Damascus is a far safer venue than Riyadh.

l The U.S. should be cautious about embracing the Sunni versus Shiite dynamic of the Syrian war. Rage against Shiites and their Iranian patrons has been a useful prop for the U.S. and Israel in mobilizing Sunni opposition against Assad, who as an Alawite is seen as part of the Shiite crescent. But this is a poisonous and potentially ruinous sectarian battle, the kind that nearly destroyed Iraq and Lebanon and is now plunging Syria into the inferno. The Saudis want to fight Shiites, yes, and further from home than Bahrain, or Al-Qatif in the kingdom’s eastern province. The U.S. should not endorse the sectarian element of this conflict.

l The U.S. should work hard (if secretly) to help the more sensible elements of the Syrian opposition, and limit the influence of extremists. This policy was ignored in Afghanistan, where the U.S. allowed Pakistan (aided by Saudi money) to back the fighters it liked — who turned out to be among the most extreme and dangerous. America is still trying to undo the mess caused by that exercise in realpolitik. Don’t do it again.

l Finally, the U.S. should subtly play the tribal card, which may be as crucial in Syria as it was in Iraq. The leaders of many Syrian tribes have sworn a blood oath of vengeance against Assad and their power is one reason why the engine of this insurgency is rural, conservative and Sunni. But Iraq showed that the tribal leaders can be the best bulwark against the growth of al-Qaida and other extremists.

What’s scary about Syria is that al-Qaida is already fighting there, in the hundreds. Cells in Mosul and other parts of northern Iraq are sending fighters across the Syria-Iraq border, with the jihadist pipeline now operating in reverse. Arab intelligence sources tell me the Syrian opposition is laudably battling al-Qaida’s influence: The opposition killed an al-Qaida fighter named Walid Boustani, who tried to declare an “emirate” in a town near the Lebanese border; they also demolished a cell that raised al-Qaida’s black flag near Bab al-Salameh, along the Turkish border. Sunni opposition fighters aren’t necessarily al-Qaida fanatics, in other words.

The rebels fighting Assad deserve limited U.S. support, just as the anti-Soviet mujahedeen did. But be careful: This way lies chaos and extremism that can take a generation to undo if the U.S. and its allies aren’t prudent.