Doyle McManus makes an unpersuasive case for “doing more” in Syria. Here is the least persuasive part:

Most important, aid doesn’t need to turn into a slippery slope [bold mine-DL]. In the 2011 intervention in Libya, Obama sent U.S. Air Force jets and Navy ships to war, but drew a line against putting boots on the ground, and that line held.

If we’re simply ignoring the role of Western and Qatari special forces in the Libyan war, then I suppose we can say that the “line held.” Granting that the U.S. was apparently able to avoid using ground forces in Libya, what does this tell us about the Syrian case? Not very much. In fact, the Libyan war is a good example of how initially very limited support for an armed uprising can quickly escalate into something much greater.

Before the Libyan intervention started, the most common proposals were to establish a “no-fly zone” and to arm Libyan rebels. We hear much the same thing now in the debate over Syria. Interventionists didn’t make these proposals because they expected that they would be sufficient, but because these “limited” measures were useful for making direct intervention more likely. There was an arms embargo imposed on Libya, which might have seemed to make the latter impossible, but some Western governments, especially France, made a point of ignoring the embargo and sending in weapons anyway. U.S. clients and allies are doing something similar in Syria now, and the U.S. has been reportedly providing “non-lethal” aid for some time. In Libya, there was nominal international consensus in favor of a “no-fly zone,” but as soon as the intervention began the U.S. and its allies went far beyond that and started waging a prolonged air war. The “line” of refusing to use ground forces in Libya held because they proved to be mostly unnecessary, at least as far as overthrowing the regime was concerned. We know that in the Kosovo war this same initial opposition to using ground forces was close to being reversed because the air war against Yugoslavia wasn’t succeeding on its own. The New York Times reported in November 1999:

In early June, Prime Minister Tony Blair of Britain, the most outspoken advocate of a ground invasion of Kosovo, had ordered the preparation of 30,000 letters calling up Britain’s army reserves. Typed and addressed, they were about to go into the mail, making possible the commitment of up to 50,000 British troops — half the standing army — to go into Kosovo.

In Washington, President Clinton, with enormous reluctance, was about to give his own approval to preparations for a ground invasion of Kosovo, including up to 120,000 American troops — despite his vow, in a televised speech on the first day of the war, March 24, that “I do not intend to put our troops in Kosovo to fight a war.”

The “line held” in Libya because the intervention “worked” in toppling Gaddafi, and it “held” in Kosovo because Milosevic capitulated before the U.S. and NATO committed to an invasion, but we have no way of knowing whether other measures short of an invasion would “work” in Syria.

McManus’ column itself is evidence that there is a nearly unavoidable “slippery slope” in these debates. There is always a chorus of people insisting that “we need to be doing more” regardless of how much the U.S. happens to be doing, and the more aggressive that U.S. policy becomes the more encouraged interventionists are that they can keep driving the debate in a hawkish direction. After all, the U.S. is currently providing some limited aid to the Syrian opposition, but because that aid is not “working” to the satisfaction of more hawkish Americans there are repeated demands that the U.S. “do more.” This is the same thing that would happen if the administration did what McManus advised by providing military aid, and then in few more weeks or months when that measure was not “working” to the hawks’ satisfaction there would be renewed calls for even more aggressive measures. Once a government commits itself openly to backing one side in a conflict with military aid, it becomes much harder to reject more aggressive measures later. At that point, the government has conceded that it is much more interested in the victory of its “side” in the conflict and much less interested in halting the conflict.

Arming the Syrian opposition is a bad idea its own merits, and not just because it could pave the way for later escalation. As I said last October:

Shortening the conflict is almost certainly not what will happen. Arming the opposition in Syria will prolong the conflict by providing at least some anti-regime forces with the means to keep fighting much longer than they could without this support. The goal of such a policy is to bring about regime collapse, which will make for even more “all-out chaotic massacres and civil conflict.” Helping to collapse the existing government will create a vacuum that terrorist groups can and will exploit.

Nothing has happened that makes the case for military aid to the Syrian opposition any more compelling than it was a few months ago. The fact remains that arming rebels in Syria has been a terrible policy option all along, and it isn’t magically going to become wise or necessary for the U.S. as more time passes.