I met Mr. Assad twice. He was suave, but three years after the peaceful protests started, his record of relying on horrific brutality to maintain power is clear. Moreover, his regime has a history of implicit cooperation with Al Qaeda, as we saw in Iraq. This is not a man with whom the United States should align itself.

Mr. Assad now depends on Iran and Hezbollah for his survival, and Iran’s influence in Syria is likely to remain as long as Mr. Assad does. Hezbollah, though, is unlikely to fight to clear eastern Syria of jihadists. None of this serves American interests.

To be sure, there is no military solution, but it is possible to salvage something in Syria by preparing the conditions for a genuine negotiation toward a new government. And that requires empowering the moderate armed opposition.

First, the Free Syrian Army needs far greater material support and training so that it can mount an effective guerrilla war. Rather than try to hold positions in towns where the regime’s air force and artillery can flatten it, the armed opposition needs help figuring out tactics to choke off government convoy traffic and overrun fixed-point defenses.

To achieve this, the Free Syrian Army must have more military hardware, including mortars and rockets to pound airfields to impede regime air supply operations and, subject to reasonable safeguards, surface-to-air missiles. Giving the armed opposition these new capabilities would jolt the Assad military’s confidence.

Even Iran would have to consider the safety of its supply flights. That caution would inform Iranian thinking and might even stir Tehran to join us in pushing for serious negotiations.

Cash for small salaries, together with reliable supplies of food, medicine and ammunition, would also put the moderate armed forces on an equal footing with the Qaeda groups that have long offered these enticements to recruit Syrian fighters. The Free Syrian Army commanders often pleaded with me for such basic items.