By Bruce Stokes, Director of Global Economic Attitudes, Pew Research Center

Special to BBC

Growing evidence that the Syrian government of Bashar al-Assad may have used chemical weapons against its own people has led to a crescendo of demands for the US to intervene in the Syrian civil war. But neither the American people, nor Europeans, nor Syria’s neighbours wholeheartedly support such a move.

The lack of sustained public backing, both in America and in the region, is the political context in which the Obama White House will “rethink all options” – as Defence Secretary Chuck Hagel put it on Thursday.

Demands for some form of American action against Assad have intensified now that the US government has acknowledged that it too, along with the British, French and Israeli governments, thinks that chemical weapons have been employed by the regime.

In a recent Washington Post op-ed piece, Anne-Marie Slaughter, the former head of the policy planning office in the US State Department, plaintively asked Obama: “Mr President, how many uses of chemical weapons does it take to cross a red line against the use of chemical weapons?”

And Senator John McCain has called for arming the rebel troops, establishing a no-fly zone over Syria and for the United States to “be prepared with an international force to go in and secure these stocks of chemical, and perhaps biological, weapons”.

But such exhortations seem to be out of step with public sentiment in the United States, in Europe and in the Middle East.

Just 45% of the American public favours military intervention in Syria, even if it is confirmed that the Syrian government has used chemical weapons against anti-government groups, according to a new poll by the Pew Research Center conducted 25-28 April 2013 among 1,003 adults in the United States. More than half (54%) of the American public opposes or has no opinion about such action.

Moreover, even such qualified American support for intervention is relatively new. In December 2012, 63% of Americans thought that the United States had no responsibility to do something about the fighting in Syria between government forces and anti-government groups.

And in a Pew Research Center survey conducted in March 2013, before news emerged of the alleged use of chemical agents, nearly two-thirds (64%) of Americans were against even arming the rebels.

At the time (March 2013) there was even less stomach for military assistance to the rebels. Eight out of 10 Germans (82%) opposed the idea, as did more than two-thirds of the French (69%) and a majority of the British (57%).

Public opinion in the region is even less supportive of Western involvement. In five of the six countries in the region that were surveyed in March – Lebanon (80%), Turkey (68%), Tunisia (60%), Egypt (59%) and the Palestinian territories (63%) – publics opposed Americans or Europeans supplying the Syrian rebels with weapons. Only in Jordan (53%) did people back Western intervention and then only barely.

People in the region do not even want their own government to get involved. Even the Turks (66%) and the Lebanese (60%), both of whom share a border with Syria and now house hundreds of thousands of refugees from the civil war, oppose Arab military aid to the rebels. And only the Jordanians (65%) back Arab countries sending arms and military supplies to anti-government groups in Syria.

This allied and regional reluctance to get involved in Syria poses a problem for the Obama administration.

As American pundits and politicians call for Syrian intervention, however merited or unjustified those appeals may be on humanitarian grounds, such pleas have yet to rally majority support for such action in America, Europe or the Middle East.