The worsening violence and repression in Syria has left policymakers scrambling to think of ways our governments could help end the bloodshed and support those seeking to dislodge the Assad regime. The desperate desire to "do something" has led to increasing calls for the United States to provide military aid to armed insurgents or even engage in direct military intervention, especially in light of the possible use of chemical weapons by the Syrian regime.

The question on the mind of almost everyone who has followed the horror as it has unfolded over the past two years is, "What we can do?"

The short answer, unfortunately, is not much.

This is hard for many Americans to accept. We have a cultural propensity to believe that if the United States puts in enough money, or creativity, or willpower, or firepower into a problem that we can make things right. While that attitude has served us well overall, it isn't always the case.

Both the right and the left seem to embrace the idea that United States-- either for good or for ill -- has the power to determine the outcome of virtually every conflict in the world. However, there are limits to power. The tens of billions of dollars' worth of arms sent to the Shah and to Mubarak were not enough to keep these dictators in power against the will of their own people. Overwhelming U.S. military force could not prevent a Communist victory in Vietnam or create

Syria is very different than Libya, where NATO air power supported an armed rebellion topple the Qadaffi regime in a bloody six-month war: The population is more than three times as large, the terrain far more challenging, the liberated zones controlled by the rebels are tiny and non-contiguous, and the Syrian armed forces -- including its anti-aircraft capabilities -- are far superior.

The other difference is that by the time the Libyan uprising began in 2011, Qaddafi had virtually no popular support. By contrast, despite everything, the Syrian regime still has a social base. A fairly large minority of Syrians -- consisting of Alawites, Christians and members of other minority communities; Baath Party loyalists and government employees; the professional armed forces and security services; and the (largely Sunni) crony capitalist class that the government has nurtured -- still cling to the regime. There are certainly dissidents and within all of these sectors, but altogether regime supporters number as much as one-third of the population.

There is also the problem that U.S. intentions are highly suspect in the eyes of many Syrians. U.S. military intervention could play into the hands of the Damascus government, which has decades of experience manipulating the Syrian people's strong sense of nationalism to its benefit. The regime can point out that the United States is the world's primary military supplier to most of the region's other dictatorships as well as the ongoing Israeli military occupation of Syria's Golan province, and disingenuously used "democracy promotion" and fabricated claims of "weapons of mass destruction" to justify its invasion of its neighbor Iraq.

Simply supplying arms to Syrian rebels could also be problematic, particularly since an increasing percentage of the armed opposition are hardline Islamists, including some who are affiliated with al-Qaida. Even the so-called "moderate" Free Syrian Army consists of literally hundreds of separate armed militias, some of which are quite radical, without a central command. A shoulder-fired missile that could defend a village from a Syrian helicopter gunship could also take down a civilian airliner.

Eighty percent of U.S. arms to Afghan rebels in the 1980s ended up in the hands of Hezb-e-Islami, the most hardline of the half dozen or so mujahedeen groups fighting the Soviets and their puppet Afghan regime. After the Soviets withdrew and Afghanistan's Communist government was overthrown, Hezb-e-Islami forces killed thousands of Afghan civilians and are now allied with the Taliban fighting American forces.

Opposing U.S. support for the armed resistance in Syria has nothing to do with indifference, isolationism, or pacifism. Nor is it indicative of being any less horrified at the suffering of the Syrian people or any less desirous of the overthrow of Assad's brutal regime. With so much at stake, however, it is critical to not allow the understandably strong emotional reaction to the ongoing carnage lead to policies that could end up making things worse.

Stephen Zunes, a Santa Cruz resident, is a professor of Politics and coordinator of Middle Eastern Studies at the University of San Francisco.