The Obama administration announced  Thursday night that, after concluding that Syrian President Bashar al-Assad's forces had used chemical weapons, it would provide direct military assistance to the rebels as a "last step." Although it has not  announced what kind of military assistance it would send, it's expected to consist mostly of small arms: rifles and bullets.

Rebel leaders say that small arms will do them little good and that they need heavier weapons. Whether or not greater U.S. involvement is a good idea, two things appear to be true: that the rebels are losing ground against Assad's forces, backed by Iran and Hezbollah, and that small arms would not turn the tide.

Why? It has to do with Assad's military strategy. New York Times correspondent C.J. Chivers, appearing on NPR's Fresh Air in late April, explained that strategy, its successes and why heavy weapons such as artillery or shoulder-launched missiles would likely be necessary to overcome it. Chivers, as a former Marine and the Pulitzer-winning author of "The Gun," a history of the Kalashnikov assault rifle, does have some direct experience in these matters. I've added some emphasis in bold.

We talked about a social shift to this country but as this point you're also seeing a tactical shift. When the Syrian military first set out in the crackdown it had the run of the countryside. It could drive around freely on the roads, it was even using the rail line. It could move almost as it saw fit and it could predictably in these large columns and patrols. That changed when the rebels developed an indigenous effort at making improvised explosive devices, or makeshift bombs. By bombing the roads, by setting up ambushes, they were able to deny sections of the countryside to the army. Certainly, the freedom of movement in the countryside, where the rebels were strong, became a thing of the past.
And the army reacted. And the army understood that when it couldn't fight this free-roaming that it needed to find a way that capitalized on its own strengths. And that strength was firepower, in some cases manpower but often just firepower. And so they went to a series of strong points, like islands, all across areas of the countryside where they were weak. And these islands are almost, in some cases, impregnable to the rebels' weapons.
If the other side is not coming out, if the other side is not exposing itself, it's very difficult to dislodge that army with rifles and rocket-propelled grenades and makeshift bombs that are waiting along the sides of the roads. It's very, very hard to gain momentum against a militarily stronger side that will not move when all you have are these weapons that you can carry on your shoulder or in your backpack.
And that mismatch persists as recently as a few weeks ago when we were traveling with groups. They still had, in the main, only rifles, machine guns, in some cases bolt-action rifles, rocket-propelled grenades and very occasionally you would see an old anti-tank system known as a recoilless gun. These tend to be relatively short-range, flat-shooting weapons that don't have an ability to dislodge a force that is bunkered in.
What you hear constantly from the rebels is not that they want a military intervention per se, but that they want equipment so that they can fight, themselves, more effectively, and the rebels would certainly like and appreciate something like a no-fly zone. But what they want and probably think is more realistic to get are weapons that will allow them to fight against these strong points and will allow them to fight against armor and will allow them to defeat aircraft that are in some cases bombing their positions and their homes and their towns. Not in some cases, actually, in many cases their homes and their towns, because a lot of the air strikes are clearly just dropped on neighborhoods.
Weapons, in the view of the guys that are doing the fighting, are the thing they need most.

Expect to hear this argument increasingly from Syrian opposition representatives. As Louay al-Mokdad, political and media coordinator for the Free Syria Army, told The Washington Post regarding the Obama administration's decision to send some military support, "We welcome the decision, but it is a late step. And if they send small arms, how can small arms make a difference? They should help us with real weapons, antitank and antiaircraft, and with armored vehicles, training and a no-fly zone."

The risk of sending any military support to the rebels is that it's not clear how the U.S. could arm moderate rebels without some of those weapons ending up in the hands of extremist fighters. Groups like Jabhat al-Nusra, the increasingly successful Islamist rebels who are allied with al-Qaeda, would likely end up with some of the arms, whether small or heavy. And these weapons don't disappear once the conflict ends, nor do they stop working if they're transferred out of Syria into, say, Lebanon or Iraq.

So the case against sending small arms is two-fold: first, it's unlikely to turn the tide against Assad's forces, for the reasons Chivers explained above; second, extremists are bound to end up with some of those guns, which they could use to terrorize Syrian civilians or foreign targets. To be clear, the case against small arms is not necessarily a case for heavy weapons, which after all could also end up in the hands of extremists. But it's easy to see why both advocates and critics of greater U.S. involvement are warning against sending small arms, which analysts such as the Brookings Institution's Shadi Hamid have called a "half measure."

Update: Chivers got in touch on Twitter, offering a "quibble." Here's a cleaned up version of what he wrote: "Many rebels remain without rifles or with little ammo. Militarily, one small step toward solving their big problems would be fixing this. And a wider distribution of machine guns and machine gun training would be very helpful for offensive tactics. On all else, you're spot on. Small arms won't change the current dynamic, although if well-selected (with ammo) they could improve rebels' lot."