The Obama administration asserts America is "not alone" in planning its proposed Syria strikes, though ally countries have yet to formally join the call for limited military action now advanced by the White House.
Whether other countries will participate in an American offensive against Syria remains to be seen. Short of an official White House list of who's in, analysts and CNN correspondents size up which countries may -- or may not -- play a military or diplomatic role in a planned U.S.-led air assault on Syria.
What about the British, our loyal ally in the Iraq War?
In a staggering setback to Prime Minister David Cameron, the British House of Commons said no to joining a U.S. assault against Syria. The United Kingdom is overwhelmingly against another Middle East conflict, with only 16 percent in favor of militarily punishing the Syrian regime.
Is there a chance UK legislators might reconsider?
It's possible, experts say, because Obama's strategy to make a public case before Congress for a limited Syria attack may win favor in Europe.
However, Cameron seemed to quash speculation that there might be a new Commons vote Wednesday.
"Britain cannot be and will not be part of any military action" against Syria, he said, adding that he respects the outcome of last week's vote and "will not be bringing back plans for British participation in military action."
The White House alleges that the Syrian regime is deploying chemical weapons that are killing innocent children and adults in a civil war that has lasted more than two years.
"It'll be interesting to watch in the coming days if the Obama administration's case on chemical weapons reverberates with the European public," said Andrew Tabler, senior fellow of the Washington Institute.
Well, who in Europe does support us?
It could be France, in something of a role reversal from 2003, when France declined to join the Iraq invasion but the British sent many troops.
The French parliament is expected to debate military action against Syria this week. But there's not a lot of nationwide support for such an intervention -- only one in three people in France endorses punishing Syria.
But the French are more open than the Germans, who are against it by a 5-1 ratio. German Chancellor Angela Merkel, who is facing re-election later this month, said her country won't participate in any military action, though she called the plight of the Syrian people "catastrophic."
Where does Israel stand on all this?
Israel, the ultimate U.S. ally in the Mideast, has already intervened in the Syrian conflict but in a measured way, using isolated bombing in instances that Israel deemed Syrian aggression.
"They have been doing this tit-for-tat thing," said Jeff Martini, Middle East analyst for the Rand Corporation.
For now, Israel is maintaining a low-profile in the international debate about whether to launch an offensive against Syria because it doesn't want to further antagonism between it and Arab neighbors. Israel's vast military force -- fighter jets, surveillance, early warning systems -- would be an important asset to American forces if an attack on Syria proceeds.
"Israel is doing its part by keeping quiet," Martini added. Israel is being supportive behind the scenes.
What about U.S. access to Turkey's air bases?
Some Turkish support will be public, and some will be under the table, said Anne-Marie Slaughter, president and CEO of the New America Foundation. The same goes for Saudi Arabia and Jordan, she said.
How a no-boots-on-the-ground attack against Syria would play out hasn't been revealed by the Obama administration.
Bombing would likely include missiles launched from the U.S. warships in the Mediterranean Sea.
The use of other countries' soil in the region for air strikes is uncertain, experts say.