About 60 percent of Americans surveyed said the United States should not intervene in Syria’s civil war, while just 9 percent thought President Barack Obama should act.

More Americans would back intervention if it is established that chemical weapons have been used, but even that support has dipped in recent days – just as Syria’s civil war has escalated and the images of hundreds of civilians allegedly killed by chemicals appeared on television screens and the Internet.

The Reuters/Ipsos poll, taken August 19-23, found that 25 percent of Americans would support U.S. intervention if Syrian President Bashar al-Assad’s forces used chemicals to attack civilians, while 46 percent would oppose it. That represented a decline in backing for U.S. action since August 13, when Reuters/Ipsos tracking polls found that 30.2 percent of Americans supported intervention in Syria if chemicals had been used, while 41.6 percent did not.

“This is not something where opposition forces have contrived something,” said Senate Foreign Relations Committee Ranking Member Bob Corker (R-TN) on Fox News Sunday. “I hope the president, as soon as we get back to Washington will ask for authorization from Congress to do something in a very surgical and proportional way.”

Rep. Eliot Engel (D-NY), the chairman of the House Foreign Affairs Committee, agreed, but said President Obama doesn’t need Congress’s approval “initially.”

“I just think that we have to move and we have to move quickly,” Engel said. “I do agree with Senator Corker that Congress needs to be involved but perhaps not initially. Perhaps the president could start and then Congress needs to resolve it and ascend to it.”

“At this juncture, the belated decision by the regime to grant access to the UN team is too late to be credible, including because the evidence available has been significantly corrupted as a result of the regime’s persistent shelling and other intentional actions over the last five days,” the statement said.

The administration has said that the use of chemical weapons would be considered a red line that would trigger a response by the United States.

Quoting Syria state television, the Associated Press reported that the Syrian government agreed to allow the U.N. team to visit the locations near the capital of Damascus.

At this point, a prolonged stalemate is the only outcome that would not be damaging to American interests.

Indeed, it would be disastrous if President Bashar al-Assad’s regime were to emerge victorious after fully suppressing the rebellion and restoring its control over the entire country. Iranian money, weapons and operatives and Hezbollah troops have become key factors in the fighting, and Mr. Assad’s triumph would dramatically affirm the power and prestige of Shiite Iran and Hezbollah, its Lebanon-based proxy — posing a direct threat both to the Sunni Arab states and to Israel.

But a rebel victory would also be extremely dangerous for the United States and for many of its allies in Europe and the Middle East. That’s because extremist groups, some identified with Al Qaeda, have become the most effective fighting force in Syria. If those rebel groups manage to win, they would almost certainly try to form a government hostile to the United States. Moreover, Israel could not expect tranquillity on its northern border if the jihadis were to triumph in Syria.

The Prime Minister spoke with President Barack Obama by telephone to ask for help with convening an emergency session of the United Nations Security Council.

He wants to put forward a “game-changing” resolution that would give the Syrian government, led by Bashar al-Assad, “one last chance” to disarm.

Mr Cameron is said to have been left sickened by images of children killed by the chemical weapons.

One charity yesterday said at least 355 people had died and 10 times that number were treated for poisoning.

Today, the world appears to be at a crossroads. The stark and compelling evidence of large-scale atrocities, including the strongly suspected use of chemical weapons outside Damascus last week, killing perhaps hundreds of people, comes amid a growing perception that a weak and divided international community is powerless and unwilling to act on crimes against humanity. A sense of impunity feeds boldness and escalation. In Damascus, Cairo and elsewhere, actors today are making dangerous decisions based on the calculation that they will not be called to account.

In these circumstances, it is the easiest thing to say that, in the case of Syria in particular, there are only bad options. That may be true. But increasingly it may be that there is a worse option: doing nothing.

This paper has resisted the calls for military intervention in Syria. It remains the case that such intervention seems a deeply perilous route, with no guarantee of success and pregnant with the risk of triggering a wider regional war. But we do appear to be coming ever closer to a tipping point, with difficult judgments ahead. The recent statements from William Hague and President Obama have raised the temperature and increased the likelihood of some form of action or sanction if it is conclusively proved that the Syrian regime is authoring chemical attacks on its citizens. Hague is right to say that “a chemical attack … is not something that a humane and civilised world can ignore”.

Yet the case for military intervention has still to be made. Obama seems intent, rightly, on getting international agreement for an even more limited form of action – securing chemical weapons or neutralising missile sites. And, looking back at Libya, Iraq and Afghanistan, who can say with any certainty that the lives of Syrians would improve in the long term if such a course of action was taken?