On Monday, Secretary of State John Kerry said it was "undeniable" that Syria had used chemical weapons against civilians, setting the stage for an expected military campaign against the regime of President Bashar al-Assad.
The response, should it come to pass, will probably consist of cruise missile strikes from the sea or air strikes. It's highly unlikely that the Obama administration would put boots on the ground, considering that only 25 percent of the American public is in favor of intervention to begin with.
Analysts warn not to underestimate Assad's forces. "Syria has one of the biggest armies in the region," Heather Hurlburt, director of the National Security Network, told The Washington Post. "It has a lot of very expensive anti-aircraft material from Russia. It won’t be like Iraq or Libya."
The United States would likely be part of a larger coalition composed of NATO members, having dropped its strategy of trying to get the blessing of the United Nations Security Council, where Russia and China have long obstructed any meaningful action against Assad.
Here is a look at how those countries and others are responding to the possibility of war.
As a permanent member of the U.N Security Council, Russia has the power to veto any resolution that comes before it, and has used its power to consistently block outside pressure on Syria, all while providing the Assad regime with an estimated $1 billion in weapons in 2012.
Despite its vocal support of the Syrian government, however, Russia is not likely to get involved in the impending skirmish. Russian Foreign Minister Sergei Lavrov said on Monday that Russia had "no plans to go to war with anyone." Still, he made his disapproval of a potential military strike known, warning against "hysteria" that could destabilize the region.
Ultimately, however, there is very little Russia can do beyond cautioning the international community about the repercussions of its actions.
"Russia won't try to stop it, but will do nothing to help legitimize it," Fyodor Lukyanov, editor of Russia in Global Affairs, told the Christian Science Monitor, adding that Russia could still hurt the United States in the future by funding its other enemies. "Moscow may find ways, through different channels, to support Iran, knowing that Iran will never stop helping Assad."
Like Russia, China has previously vetoed efforts by the U.N. to impose sanctions on the Syrian government. China is the third-largest importer of goods to Syria and has counted on Assad's strong support when it comes to sensitive issues like the status of Taiwan and human rights.
Beijing, however, has been more cautious than Moscow in defending Syria. Chinese Foreign Minister Wang Yi on Monday said, "China resolutely opposes the use of chemical weapons no matter who uses them," claiming that the U.N. should "open an independent, objective, fair, and professional investigation."
He made it clear, however, that China opposes military intervention.
"The only way out for the Syrian issue is a political resolution," Wang said. "All parties ought to cautiously handle the Syrian chemical weapons issue to avoid interfering in (efforts) to resolve the Syrian issue politically."
Israeli Prime Minister Benhamin Netanyahu has been one of the most vocal critics of Assad's regime, using his bully pulpit to urge the international community to respond to Assad's alleged use of chemical weapons.
But an Israeli official told Haaretz that the country was looking to "keep a low profile" when it came to its neighbor. While the two countries are technically still engaged in a years-long war, Israel has mostly worked behind the scenes in the current conflict.
"Israel has no real interest in entering the whirlwind that is the bloody civil war in Syria, or even in taking sides," Amos Harel wrote earlier this year in Haaretz, noting that an "all-out war between Israel and Syria" would "seriously harm the Israeli home front."
That hasn't stopped thousands of Israelis from buying gas masks in fear that Assad could turn his chemical weapons against Israel in retaliation to a military strike by Western powers.
"We live in a crazy region," Victor Bracha, who was buying a gas mask in a Jerusalem shopping mall, told Reuters. "All it takes is for one crazy person to push a button and you never know, everything can go up in flames."
While lawmakers in Israel have been split over whether to support U.S. military intervention, experts told NPR that the Israeli military is unlikely to provide anything more than intelligence to NATO forces, although that could change if the Assad decides to attack Israel directly.
Syria's southern neighbor has already been severely affected by the unrest, taking in more than 550,000 refugees since the conflict began some three years ago. Western and Arab military leaders are currently meeting in Jordan, although Jordanian Foreign Minister Nasser Judeh stressed that it was "not a reaction to what happened recently in Syria," but rather "one of a series" of pre-planned meetings.
Judeh's caution can be explained this way: Jordan believes that if it "appears in any way to become a spring board for strikes on Syria, it will suffer," says CNN's Nic Robertson, since it would not take much for Assad's forces "to turn Jordan into turmoil."
As the region's sole NATO member, Turkey is an extremely important ally for the United States. And Turkey is 100 percent behind military intervention.
"If a coalition is formed against Syria in this process, Turkey would take its place in this coalition," Turkish Foreign Minister Ahmet Davutoglu said on Monday. "Those who commit war crimes and crimes against humanity must definitely be punished."
Turkey has opposed Assad for the entirety of the two-and-a-half-year conflict, taking in refugees and allowing Syrian opposition groups to organize on its soil. It has also been an advocate for enforcing a no-fly zone. If NATO forces do decide on air strikes, they would most likely be launched out of the Incirlik and Izmir U.S. military bases in Turkey.
France has been the most hawkish Western country during the course of the Syrian conflict, so it was no surprise on Monday when French Foreign Minister Laurent Fabius said, "The only option that I can't imagine would be to do nothing."
William Hague, Britain's foreign secretary, echoed that sentiment by saying that military action could be the only response left to Syria's alleged use of chemical weapons, saying that NATO should act even "without complete unity on the U.N. Security Council."
Germany has been more reluctant to get involved in Syria, but will likely join the U.K., France, and the United States if those three decide to take action.