Story highlights Many people are calling for military intervention to stop the bloodshed in Syria

For many reasons, however, nations are hesitant to commit themselves to the conflict

Some believe sanctions are working and will eventually turn the tide against Bashar al-Assad

As the death toll grows in Syria, so do the desperate pleas for help.

"What is the world waiting for?" asked one Syrian woman this week while holed up in a makeshift bomb shelter with her sick son. "For us to die of hunger and fear?"

The United States, the European Union, the Arab League and Turkey are all enforcing sanctions against Bashar al-Assad's Syrian regime, but the violence has only worsened in recent weeks. Government forces have pounded Homs and other anti-Assad strongholds, devastating homes and leaving many people dead or wounded.

That has only intensified the fierce debate over whether the international community should be doing more to stop the bloodshed. Many have mentioned arming the opposition or providing the same kind of air support that was given to Libyan rebels last year.

But there is a hesitancy right now to intervene militarily, and here are some of the major reasons why:

There is no international consensus.

This is the most obvious hurdle. Last year, the U.N. Security Council voted to impose a no-fly zone in Libya and use "all necessary measures" to protect its people from Moammar Gadhafi.

But the council is not unified on Syria. China and Russia, two Syrian allies, vetoed a resolution earlier this month that would have condemned the Syrian regime and provided legitimacy for a Libya-like intervention if necessary.

"The Chinese and Russians are dead set against (intervention)," said CNN's Fareed Zakaria in a recent blog post . "So it couldn't happen through the United Nations. There would be effectively a kind of unilateral or NATO operation with no international legitimacy."

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Nobody seems to want to go it alone on this one, at least not yet . But the idea isn't without its supporters. A group of prominent U.S. conservatives, for example, recently called for the Obama administration to " take immediate action " despite the vetoes.

That could be the worst possible thing to do, according to Rami Khouri, who runs the international affairs program at the American University in Beirut.

"I think foreign military intervention would probably be catastrophic, and to hear Americans suggest this is to think back what they did in Iraq and what an extraordinary catastrophe that has been," Khouri said on "Fareed Zakaria GPS."

We don't know the opposition well enough.

Many questions still surround the Syrian opposition. Who's in charge? Are they unified? Are they strong enough to mount a serious challenge to al-Assad's regime? Can they be trusted?

"Until we're a lot clearer about who they are and what they are, I think it would be premature to talk about arming them," U.S. Gen. Martin Dempsey, the chairman of the Joint Chiefs of Staff, told Zakaria in a recent interview

In Libya, rebels operated out of a large base in Benghazi, an anti-Gadhafi stronghold. The rebels in Syria don't have anything like that. They don't control much territory at all.

"They have tiny little enclaves that we're seeing being shelled right now," said CNN's Nic Robertson, who visited the country a few weeks ago.

Many just feel that it is just too risky to give weapons and support to what is still an uncertain entity.

"Until the Syrian opposition truly unifies, gains some credibility in the eyes of the Syrian people and effectively coordinates ... the Syrian uprising is not likely to go very far," wrote Bilal Y. Saab, a visiting fellow at the Monterey Institute of International Studies.

Al-Assad still has strong support in his country.

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Syria is very much divided.

"Al-Assad still has 20% to 30% support of the population," Robertson said. "They still buy his message that he is fighting terrorist groups who are backed by an international media conspiracy."

Many of al-Assad's supporters are Christians and Alawites, the Shiite sect to which he belongs. Most of the country's rebels are Sunni Muslims.

"The message that Assad sells his people is that you're only going to be safe under me," Robertson said. "The Sunni majority, if they get power, (will force you) out of your homes and businesses."

Perhaps most importantly, al-Assad still has the support of Syria's army -- one that is much stronger, better equipped and more unified than the one in Libya.

All of this makes military intervention very difficult

"As long as Damascus, Aleppo, most mosques, schools and the bulk of the armed forces support (al-Assad), we would be mistaken to underestimate the risks of an all-out war, sectarian bloodshed and rival tribal fighting," said Ed Husain, senior fellow for Middle Eastern studies at the Council on Foreign Relations.

Geography is an issue.

There are geographical concerns that have to be taken into account when considering military intervention in Syria.

Libya was relatively easy last year. Most targets were close to the Mediterranean coast and NATO air bases in Italy.

But Syria has a much smaller coastline than Libya (roughly 119 miles vs. 1,110 miles), and neighboring countries probably won't be very accommodating for supplies, troops or anything else that might be needed in the mission.

Iraq and Lebanon have their own sectarian issues , writes CNN's Tim Lister. Jordan would likely be hesitant to help, too, and Israel is out of the question. Turkey would be the most likely staging ground, but they have risks to consider as well.

Topography also is a concern, Lister says. Syria is much more mountainous than Libya, and that would make fighting -- not to mention travel -- much harder.

Some believe sanctions could still work.

The U.S. isn't taking any long-term options off the table, but right now it's committed to clamping down with tougher sanctions, not arming the opposition.

"Our strong preference is not to fuel what has the potential to become a full-blown civil war," said Susan Rice, the U.S. ambassador to the United Nations.

Rice is optimistic that the al-Assad regime is on its last legs, telling CNN's Wolf Blitzer that "the pressure is increasing, the economy is crumbling."

The hope is that economic difficulties will eventually turn more of the Syrian people, including its soldiers, against al-Assad

"The tipping point, I believe, is the social balance of forces inside Syria," said Fawaz Gerges, director of the Middle East Study Center at the London School of Economics. "Once the middle class fully joins the uprising, Assad is a goner."

"It's not like Saudi Arabia," he said. "It can't bribe its people. It doesn't have that kind of ability even to bribe the army.

"Eventually, they're going to face real cash shortfalls. And what that means going forward is a really interesting question. This is not a regime that can outlive the sanctions and all this pressure unendingly. They have got one source of cash right now: Iran. And that, too, is drying up."

Perhaps the key question to ask right now is, how long do you wait? With people dying every day, when do you say enough is enough and give up on sanctions?