President Obama was confronted with the anxieties of the Middle East yesterday when the first question he received at his press conference with Benjamin Netanyahu was about Syria. “Morally,” began the question ominously, “how is it possible that for the last two years, tens of thousands of innocent civilians are being massacred and no one, the world, the United States, you are doing anything to stop it immediately. On a practical level, you have said today and also in the past, that the use of chemical weapons would be the crossing of a red line. It seems like this line was crossed yesterday. What specifically do you intend to do about it?”

Obama began his answer by noting that there is no proof or consensus on whether chemical weapons have, in fact, been used. Then he pushed back on the accusation he’s done nothing: “It is incorrect to say that we have done nothing. We have helped to mobilize the isolation of the Assad regime internationally. We have supported and recognized the opposition. We have had hundreds of millions of dollars in support for humanitarian aid.”

That wasn’t much of a response, because the question was what is being done to “stop it immediately,” and nothing the West is doing would seem to qualify. And in fact the reporter’s question was representative of the current mood here in the States as well, in which calls for Obama to intervene in Syria are growing as quickly as the wisdom of such intervention seems to be fading.

At the outset of this conflict, there was a vacuum. That vacuum presented the United States with an opportunity to shape who would step into the breach, and how. The Obama administration made the mistake of standing aside and letting countries like Qatar distribute money and weapons to the rebels. Unsurprisingly, this resulted in the emergence of Islamist groups like the al-Nusra Front leading the way. That was followed by the head of Israel’s military intelligence claiming that Iran has set up a local army–modeled, presumably, after Hezbollah–in Syria of 50,000 men with plans to expand it to 100,000. Iran’s proxy control, if established, would essentially enable it to control forces on yet another of Israel’s borders and would give it hegemony stretching straight through to the Mediterranean. As Walter Russell Mead noted, this would also embolden Iran’s drive for nuclear weapons by convincing the mullahs that Obama doesn’t mean what he says and isn’t willing to back up his threats with force. After that came the news that al-Nusra and other Islamist rebel groups have established a “Sharia Authority” to enforce Sharia law in rebel-held areas, beating sinners with lead pipes.

Carl Levin, the Democratic chairman of the Senate Armed Services Committee, and John McCain co-authored an open letter to President Obama today urging him to consider establishing a no-fly zone and a safe haven inside Syria, as well as increase help to the rebels. Mead made his own recommendation:

The President needs to act. None of the choices are particularly good at this point, and his political adversaries should cut him some slack here. Any US effort will not be a surgically effective operation that helps only the good people. There will be consequences to intervention in Syria and we won’t like all of them. Sending in US troops would be an enormous mistake; arming selected rebel groups is a much better choice.

Mead acknowledges that feeding American weapons to the rebels will very likely result in some of those weapons being used to commit atrocities. But, he adds, “defeating Iran’s bid for continued influence and control in a strategically vital country is a prize big enough at this point in Middle Eastern history to justify running some risks and accepting some costs.”

But the Iranian force being set up, according to Israeli intelligence, isn’t part of the Syrian army–it’s a parallel army. That means it’s there not to prevent Assad’s fall—though Iran would surely like to do that—but to presume Assad’s fall and plan accordingly. It would be, like Hezbollah in Lebanon, a powerful independent actor. Will arming less troublesome, and noticeably weaker, rebel factions shift the balance of power? The case of Lebanon, in which there was an existing army and experienced political class that were both aided by the U.S. and still proved unable to resist Syrian/Iranian hegemony and Hezbollah’s empowerment, does not provide cause for optimism.

There will be no American invasion of Syria. And there certainly will be no NATO-led occupation force to do in Syria what the allies did in Iraq. It’s possible that those who want to step up arms and assistance to the rebels are right, and that it will tip the scales. But it’s at least as possible that it will lead to the further strengthening of bad actors. It’s clear that there have been consequences to the wait-and-see approach. It’s less clear if they can be reversed.