It is hard to exaggerate the Obama administration’s degree of confusion over Syria. On the one hand, the president has said that Bashar Assad should go and vowed to enforce his famous “red line” against the use of chemical weapons. On the other hand, as the Wall Street Journal reports, the administration still has not supplied arms to the rebels, as it vowed to do all the way back in June. Why not? According to the Journal: “The Obama administration doesn’t want to tip the balance in favor of the opposition for fear the outcome may be even worse for U.S. interests than the current stalemate.”

Granted, there is a risk of what will come after Assad–but that risk has only grown because of the administration’s vacillation over the past two years. Lack of American support for the moderate opposition factions has allowed jihadists to grow stronger, even if they are still not, as widely believed (and as claimed by Assad), the dominant force in the rebel coalition. The administration’s argument is circular and self-fulfilling: We won’t back the moderate rebels, so the extremists grow stronger, providing further arguments against providing any help to any rebel faction.

Admittedly, it would have been much better to start arming and building up the moderate opposition two years ago. But we have no choice but to try now, otherwise the victor is either going to be the Iran-Hezbollah-Assad axis or al-Qaeda and its ilk. Neither one speaks for the majority of Syrians and there is still an opportunity–albeit an opportunity much smaller today than two years ago–to buttress the more moderate factions of the Free Syrian Army. But in order to do that the Obama administration will have to provide heavier weapons to vetted rebel factions, especially anti-tank missiles that can stop Assad’s armored vehicles.

The rebels also require anti-aircraft missiles to shoot down Assad’s aircraft. The administration is on more solid ground in refusing to grant this weapons request because of the danger that portable anti-aircraft systems such as the Stinger could fall into the wrong hands and wind up being used against civil aviation. As I have been arguing for a while, instead of providing anti-aircraft missiles to the rebels, the U.S. and its allies should simply use their air and naval forces to ground Assad’s aircraft. That could be achieved from stand-off range by cratering runways and blowing up aircraft on the ground. It would be achieved even more surely by imposing a no-fly zone backed up by airstrikes; Assad’s anemic air defenses, weakened by defections and two years of fighting, would be no match for an American-led air assault.

Unfortunately there is little indication that, even if granted the power to act by Congress, Obama will take any of these steps. More likely are a few days of cruise missile strikes expressly designed not to topple the Assad regime–and not even to eliminate its chemical weapons arsenal because of the threat that air strikes could simply disperse dangerous chemicals into the air. Of course Assad, because he reads the news too, knows all this. The New York Times quotes a former friend of his: “This is what Bashar Assad has told the top elite: that it will be a cosmetic attack. They believe it deeply.”

It is critically important to upset Assad’s expectations–to ensure that an American attack, if there is one, is not simply cosmetic. Congress cannot force Obama to act decisively, but with a lopsided vote for a strong resolution which gives the president full freedom of action, it can at least create the conditions for decisive action should administration hawks, led by Secretary of State John Kerry, prevail in their internal deliberations.

The alternative–of not granting the administration authorization to act–is too dangerous to contemplate: It would be a green light to WMD proliferators from North Korea to Iran who will now know that the U.S. will do nothing to stop them. Thus, congressional skeptics have no choice but to hold their noses and vote “aye,” all the while hoping that the administration’s use of force will be less anemic than widely advertised.