There is more than enough blame to go around for the military coup in Egypt and subsequent events, and the United States is not exempt.

As in El Salvador, Nicaragua, East Timor, Angola, Lebanon and Gaza in previous years, the killing of civilians in Egypt has been made possible by U.S.-provided weapons used by a U.S.-backed government. As a result, the Obama administration and Congress are morally culpable through their support of the repressive military regime responsible for most of the killings.

As with some of those other cases, there are members of the opposition who have contributed to the bloodshed and bear some responsibility. Elements of the Muslim Brotherhood and its supporters have attacked government buildings, opposition protesters, churches and more, and many of them have been armed. This comes in the wake of the Brotherhood squandering its year in power through its insistence on shaping the politics of the post-Mubarak era solely on its own terms rather than through a coalition, imposing unpopular conservative policies, and ruling in a semi-autocratic manner. The Brotherhood so alienated the majority of Egyptians that millions took to the streets in protest, prompting a coup that was initially quite popular.

However, the vast majority of Egyptians killed since the coup have been unarmed civilians engaged in peaceful protests who were struck down with American-made weapons by soldiers transported in American-made vehicles provided by the American taxpayer. And whatever one thinks of the Muslim Brotherhood's politics or leadership style, nothing justifies the massacre of hundreds of protesters and bystanders.

Many liberals were naive to trust the military. They were grateful that the military belatedly allied with them to push Hosni Mubarak aside and allied with them again to oust Mohamed Morsi. However, many forgot that military leaders are more interested in maintaining ultimate control than democratizing society, even if they have to unleash unprecedented waves of terror on the streets of Egypt's cities.

Despite the killings, the Obama administration has refused to suspend any of the $1.3 billion of arms sent annually to the Egyptian military or even to acknowledge that the seizure of power in early July was a coup. As long as the U.S. continues to arm, fund and train the Egyptian military, Egyptians and others are going to hold the United States partly responsible, furthering anti-Americanism in the Middle East and beyond.

The violent turn in Egypt is particularly tragic because the downfall of the U.S.-backed Mubarak dictatorship had been largely nonviolent. In many ways, Mubarak's overthrow was a continuation of the global pro-democracy struggle through strategic nonviolent action, which has brought down dictatorships from the Philippines to Poland and from Chile to Serbia. Unfortunately, the Egyptian military, which assumed control after the mass civil insurrection drove Mubarak from power, refused to hand power over to the liberal democrats who led the revolution, maintained its corrupt hold on key sectors of the economy, and continued to suppress dissent. Washington rarely complained and continued to supply huge amounts of military aid.

Thanks to decades of repression by the notoriously brutal and corrupt Mubarak regime, civil society -- despite growing markedly over the past decade -- was relatively weak and inexperienced. As the time for the country's first free elections approached, the young idealistic activists who were so tactically brilliant in the 2011 revolution found they didn't have the kind of experience or financial resources held by the seasoned leadership of the Muslim Brotherhood or the military. Despite this, the more liberal/democratic/secular candidates received a majority of the vote in the first round. Because they split it among themselves, however, the runoff election was between the top two vote-getters: the Muslim Brotherhood's Morsi and the military's Ahmed Shafik, the worst possible outcome for the pro-democracy forces that ousted Mubarak. Morsi narrowly won.

Though eking out a slim majority of the vote in the runoff, the Brotherhood has never had more than a plurality of support to begin with and lost much of that once it came to office.

Still, there are tens of millions of Egyptians who recognize that their party won the freest election in Egyptian history and were forcibly removed from power and hundreds were gunned down when they protested. This is not likely to encourage moderation or compromise.

The struggle in Egypt is not about religion. The vast majority of Morsi's pro-democracy opponents who took to the streets in largely nonviolent protests during the year the Muslim Brotherhood was in power were observant Muslims. Furthermore, despite some power struggles between Morsi and some military leaders while he was in office, they were quite willing to cooperate in suppressing the Egyptian left.

In many respects, ever since Mubarak's ouster, it has been a three-way struggle between liberal democratic forces, the Islamists, and the military, with the military playing one side against the other. The military has ruled Egypt for most of the past 60 years. It controls as much as one-third of the economy, and has proven its willingness to do whatever it takes to stay in power, from switching sides in the Cold War to massacring its own people.

As a result, while the United States was clearly unhappy with Morsi's victory in last year's election, the sense was that the military had enough leverage to keep the Muslim Brotherhood from doing much to hurt U.S. interests. Despite its extreme antipathy toward Israel, the Brotherhood was pragmatic enough not to try to threaten the Jewish state, given its vast military superiority. And as a movement dominated by wealthy businessmen, they were quite willing to cooperate with U.S. economic interests and international financial institutions.

There is no apparent evidence to suggest the United States was behind July's coup. It came as a result of the massive and largely nonviolent uprising demanding Morsi's ouster. Unfortunately, as with the ouster of Mubarak two years earlier, the military hijacked the popular struggle.

In short, both the military and the Muslim Brotherhood are wrong. Neither is concerned about democracy and both are willing to use violence. The last thing the United States should be doing is continuing to pour more and more arms into this tragic and chaotic situation.

[Stephen Zunes is a professor of politics at the University of San Francisco.]