DOHA, Qatar >> In recent weeks, the growing death toll in Syria pushed that country’s civil war to the top of the Obama administration’s agenda, with some Arab leaders pressing harder for a greater American role in toppling Syria’s leader, Bashar Assad.

Then came the protests of the past week in the Middle East — a vivid illustration that the United States’ support for greater democracy in the Arab world during the past two years is no guarantee against the incendiary power of Islamist sentiment and anti-U.S. rage.

The turmoil has only sharpened a painful quandary that had been largely overshadowed by the presidential campaign. Should the U.S. and its allies remain wary of toppling Assad, one of the region’s last secular dictators, whose rule, however repressive, has kept the forces of populist Islam in check? Or do the protests underscore the risks of inaction, with a rapidly growing jihadi presence in Syria that is likely to further destabilize the entire region?

Already, the attacks on U.S. and European diplomatic posts, and especially the deaths of an ambassador and three other Americans in Libya, have roused calls in the U.S. for disengagement from the Arab world and its seemingly endless mayhem. That a shoddy 14-minute video lampooning the Prophet Muhammad can provoke such anger, some say, bodes poorly for any future investment in Arab democracy.

Yet those calls to disengage, some analysts say, threaten to eclipse the larger context in Syria, where rising sectarian bloodshed and a growing al-Qaida presence on Israel’s doorstep could, if left unchecked, prove far more damaging to American interests than the latest turmoil.

“You can see why the U.S. would want to disengage after what just happened in Cairo and Benghazi,” said Salman Shaikh, the director of the Brookings Doha Center. “But, in fact, the chaos and the Islamists we saw in Libya should be a warning to us about this policy of standing back. Syria could become far, far more dangerous than Libya for the United States and the region, and it’s still not too late to make a difference.”

The death toll in Syria has sharply increased in recent weeks, with some estimates putting it at more than 23,000. Regional powers like Turkey and Saudi Arabia, which now provide a trickle of light weapons to the rebels, have made it clear that they will not play a more decisive role without U.S. support.

At the same time, the increasingly sectarian nature of the conflict and the danger of becoming involved in a proxy war with Iran and Russia, which continue to provide military support to the Syrian government, have kept the Obama administration and its European allies cautious. Looming over any potential intervention is the specter of Iraq, where a sectarian civil war devastated the country in 2006 and 2007 despite a major U.S. military presence.

One senior administration official, speaking on the condition of anonymity, said the attacks on U.S. embassies last week demonstrated the soundness of President Barack Obama’s approach, which involves providing humanitarian and logistical aid but not weapons to the rebels. Obama has been criticized by Republicans, including Sen. John McCain of Arizona, who has advocated a military approach, and Mitt Romney, the party’s presidential nominee, who proposes arming the opposition via intermediaries but not directly.

Any effort to intervene militarily in Syria would probably take place without the imprimatur of the U.N. Security Council, where Russia has consistently opposed it.

“These incidents will further give people pause because already our intelligence agencies have been telling us that amongst the Syrian opposition — the people who we’re supposed to support — some of them are al-Qaida affiliates,” said Brian Katulis, a national security expert at the Center for American Progress, a research and advocacy organization with close ties to the Obama White House.

Adding to the complexity of the Syria issue is the connection with Iran and the debate in the U.S. and Israel over whether to use airstrikes to stop Iran’s nuclear program. One argument for toppling Assad has been to weaken Tehran, which has depended on Syria as its lone Arab ally and conduit to Hezbollah and other anti-Israel groups. Iran’s economy is already buckling under sanctions, and if Iran lost Syria’s support, it might be more amenable to a compromise over its nuclear program, or so the theory goes.

But it is far from clear that Western intervention in Syria would succeed in ousting Iran, which has deep networks in the country and might prove more adept than any Western or Arab power at operating in a chaotic, post-Assad Syria.

Some proponents of intervention argue that it is likely to take place at some point, and that by then the U.S. and its allies will have fewer options. Obama has already said he would step in if Syria appeared ready to use chemical weapons, and a vastly increased death toll — or the threat of genocidal attacks on one of Syria’s religious or ethnic minorities — would create much greater pressure to intervene. If the rebels succeed in toppling Assad on their own, the resulting chaos and power struggle would also create a strong incentive for intervention.

“The risk of not intervening is not just that you create greater operating room for jihadis,” said Emile Hokayem, a senior fellow at the International Institute for Strategic Studies. “You also risk not having any allies on the ground the day after Assad falls,” and no power to shore up moderates in the new Syria.

Apart from the question of intervention, the latest anti-American protests could influence the way the U.S. allocates the limited support it has been providing to the rebels fighting Assad’s government.

“The focus so far has been on identifying rebel groups to support” and weeding out the more Islamist elements, Hokayem said. “You can be sure those categories are going to harden.”

Officials with the Free Syrian Army, the main rebel opposition group in Syria, have been in Washington calling for the U.S. and other nations to establish a partial no-fly zone over Syria.

Administration officials close to Obama say that while he remains opposed to military intervention in Syria, the events of the past week have not turned him away from any kind of engagement with the opposition.

Friends and associates of J. Christopher Stevens, the U.S. ambassador killed during the attack in Benghazi, say the last thing that he would have wanted to see was the U.S. retreat from the Arab world, including Syria. Stevens was considered for a top post at the embassy in Damascus, the Syrian capital, before he decided to go to Libya.

“Chris believes, and would say, ‘This takes a robust form of diplomacy that we’re not good at because we’re used to dealing with dictatorships,”’ said Andrew J. Tabler, a Syria expert for the Washington Institute for Near East Policy. “He knew there were risks. What I’m worried about is if Libya is used as an excuse for the United States to pull back from the region. The reality there has just changed, and the people now are a factor in these countries.”

© 2012 The New York Times Company