So, the Obama administration has now decided that Syria’s use of chemical weapons crosses a red line and, as a result, the United States will supply the opposition with small arms and ammunition.  This strikes me as a risky decision – too little to have a real impact and enough to commit the United States in a complex civil war.

First, let’s be clear. This will not ease the humanitarian nightmare unfolding in Syria. The opposition forces will now have some more arms and will fight back, presumably killing more of the regime’s soldiers and supporters. Levels of violence might well rise not decline.

So what exactly is the objective of this policy shift? Is it the defeat of Bashar al-Assad? If so, can such a small shift in American support for the opposition really do that? The opposition forces are disorganized. Joshua Landis, the Syria scholar, estimates that there are 1,000 militias that make up the rebel forces. Such a decentralized opposition would need a lot more than more small weapons and ammunition to succeed.

If they did succeed, that would be a good outcome. But it will almost certainly mean that the various militias would then begin a massacre of the Alawites, the sect that the al-Assad regime comes from. It is unclear what would happen to the Christians and Kurds, who have tended to stay neutral in this conflict, but they too might feel the wrath of newly empowered Sunni militias. The Alawites, Christians, and Kurds collectively make up about a third of Syrians, so this could become an even-larger, many-cornered struggle. Remember, with 180,000 troops in Iraq, we could not stop massacres, ethnic cleansing and massive human rights violations. We are now planning to achieve lofty ends with almost no means.

More from GPS: Why Obama needs to act on Syria

The most likely scenario is that this small step up in American assistance will not make much difference. At that point, pressure will build on the Obama administration. Sen. John McCain will make speeches saying that now, America’s credibility is on the line. Having supported the opposition, we have to ensure that they succeed. The administration will face a choice between seeming ineffectual or plunging deeper into a complex and bloody civil war.

It’s possible that the administration can just stand pat and do the little that it is doing. That could be a brutal but effective strategy to bleed America’s enemies. Contrary to much of the media commentary, the fact that Iran and Hezbollah are sending militias, arms, and money into Syria is not a sign of strength. It is a sign that they are worried that the Syrian regime might fall and are desperately seeking to shore it up. Keeping them engaged and pouring resources into Syria weakens them substantially. But can the United States pursue such a cold-blooded strategy of realpolitik?

Former President Bill Clinton recently said that he favored some American intervention because “Sometimes it's just best to get caught trying, as long as you don't overcommit.” That suggests that supporters of interventions see it as some kind of symbolic policy, to show that we care. But it is like trying to get a little bit pregnant. The outcome is rarely what you want.