US President Barack Obama was in no mood to seek congressional blessing, and his administration once built up its case to a point in the past days that a military attack on Syria seemed impending.

However, the president announced on Saturday that he would obtain congressional approval before ordering military strikes on the Syrian government to punish its use of chemical weapons last week, a dramatic turnaround that is deemed a gamble.

"We should have this debate"

"I will seek authorization for the use of force from the American people's representatives in Congress," Obama declared in a statement made at the White House Rose Garden, with Vice President Joseph Biden standing at his side.

The president said: "We should have this debate. I respect the views of those who call for caution, particularly as our country emerges from a time of war that I was elected in part to end."

"The issue is too big for business as usual," he added.

In fact, Obama does not have to go to Congress for a seal of approval, just as he did not when he ordered air raids on Libya in March 2011 in what he and his allies called a mission to protect the civilians from massacre by the Gaddafi government.

The War Powers Resolution, passed by Congress in 1973, demanded that presidents obtain an authorization before sending troops into "hostilities" or "situations where imminent involvement in hostilities is clearly indicated by the circumstances" to keep the operation going beyond 60 days.

In practice, presidents since have ignored the resolution and simply notified Congress of their operations.

And the Obama administration is weighing "limited" operation that would reportedly last only days and involve sea-launched cruise missiles or possibly long-range bombers.

"This would not be an open-ended intervention. We would not put boots on the ground," Obama said Saturday, echoing a refrain repeated by his administration in the past days. "Instead, our action would be designed to be limited in duration and scope."

"An enormous gamble"

Obama's announcement came a surprise and some see it as a gamble.

"The timing of an authorization vote is now up in the air, as well as its outcome," the Politico website said.

"President Obama's decision to ask Congress to authorize military strikes represents an enormous gamble for the White House that could have lasting repercussions for presidential power," said The Hill, a congressional newspaper.

"It is by no means clear that the (Republican-dominated) House will approve military action against Syria, given opposition both from conservatives and liberals in the House," the paper noted on its website.

The lawmakers are currently on a five-week summer break and will not return to session until Sept. 9. And Obama has no intention to bring them back early.

"Though many lawmakers praised the fact that the president would now seek their backing for military intervention in another Middle Eastern country, some speculated that the vote might fail -- and still others said Obama seemed weak for seeking their stamp of approval," the Politico wrote in an article.

Ranking Republican senators John McCain and Lindsey Graham, who have advocated deeper US involvement in Syria's conflict, said they cannot "in good conscience" support isolated military strikes not part of a broader strategy that would "change the momentum" on the ground and oust President Bashar al-Assad.

The White House on Saturday evening sent Congress a draft resolution that authorizes a US military action against the Syrian government and seeks only to "deter, disrupt, prevent and degrade the potential" for future uses of chemical weapons or other weapons of mass destruction.

Marco Rubio, an influential Republican senator, also said "the United States should only engage militarily when it is pursuing a clear and attainable national security goal. Military action taken simply to send a message or save face does not meet that standard."

Republican senator Ron Johnson said if a vote were held right now, it would fail. He said: "Right now there are far too many questions unanswered."

During a telephone briefing for the Congress leadership on Thursday evening, the lawmakers pressed senior administration officials about a range of issues, including how military operations in Syria would be funded.

The officials offered no answer, but Defense Secretary Chuck Hagel agreed it was an important question and pledged to provide additional information before or soon after any attack is launched.

"If all this is about because President Obama drew a red line and he's concerned about his credibility and restoring his credibility, that's not enough justification for me," Senator Johnson said.

Credibility gap is just what many analysts say a factor in driving Obama to a military confrontation with Syria.

"American people don't want it"

Soon after the opposition accused the Syrian government of launching a sarin gas attack on Aug. 21 in the suburbs of Damascus, Syria's capital, the Obama administration made quick efforts to build up its case on a retaliatory attack.

Obama and his administration officials said time and again that the norm regarding the use of banned weapons must be kept in place and that the al-Assad regime must be held accountable to deter others.

Britain, France and Turkey all publicly voiced their support for the military action, and tensions were heightened in the Middle East as countries took contingency measures one after another in response.

In a stunning defeat, however, to British Prime Minister David Cameron and his allies, Britain's House of Commons on Thursday rejected a government attack plan.

Though the vote is not binding, Cameron pledged not to circumvent the parliament for military action against Syria.

The Obama administration struck a defiant tone, with its officials saying Washington might take a unilateral action on its own timeline.

In its efforts to further the case, the White House on Friday released an unclassified US intelligence report, which concluded with "high confidence" that Syrian government forces had used chemical weapons multiple times in the last year, and that the gas attack on Aug. 21 left at least 1,429 Syrians dead, among them 426 children.

And then Obama backed down on Saturday following a meeting with his national security team.

"Our military has positioned assets in the region," Obama said in his Rose Garden statement. "The chairman of the Joint Chiefs has informed me that we are prepared to strike whenever we choose. Moreover, the chairman has indicated to me that our capacity to execute this mission is not time-sensitive; it will be effective tomorrow, or next week, or one month from now."

The Obama administration's plan to launch a military strike against Syria "is being received with serious reservations" by many in the US military, which is coping with the scars of two lengthy wars and a rapidly contracting budget, the Washington Post said in a report, quoting current and former officers.

Moreover, an NBC News opinion poll released Friday showed 50 percent of American voters oppose military intervention in Syria.

While Obama was speaking inside of the White House on Saturday, an anti-war protest broke out just outside.

"There should be no war against Syria," Brian Becker, director of Answer Coalition, the organizer of the protest, told Xinhua.

"The American people don't want it. It's illegal, it's immoral, it's not right. The American people are sick and tired of war, war after war after war after war," he said.