(c) 2013, Bloomberg News.

(c) 2013, Bloomberg News.

WASHINGTON The U.S. Congress is by no means certain to give President Barack Obama the go-ahead to attack Syria, a stance that would pose a political obstacle to any military strike and prolong a looming showdown on Obama's domestic agenda.

Republicans and Democrats alike praised Obama's decision Saturday to seek congressional approval to attack Syria. Few offered quick support for his decision to strike, and there are no plans so far for Congress to return to Washington for a vote before the scheduled Sept. 9 start of the fall session.

Instead, lawmakers called for a debate over the virtues of an attack, which may add to the gridlock that paralyzed almost all of Obama's domestic agenda this year, including government spending, the debt ceiling and changes in immigration law.

''Syria may be a very easy vote for Congress to vote against," Ron Bonjean, a Republican strategist and former House and Senate leadership aide, said in an interview. "It's not necessarily a slam dunk for the president to go and act."

Obama's call for congressional approval adds to an already crowded legislative calendar. The House is scheduled to be in session for nine days before government funding expires Sept. 30. That debate would be followed by negotiations to raise the nation's borrowing authority by mid-October. The House has yet to take up efforts to alter immigration laws, after the Senate passed legislation this year.

In seeking an up-or-down vote on military action Saturday, Obama didn't say he was giving Congress veto power over the decision and left open the possibility that he would go ahead without lawmakers. At the same time, he repeatedly cited the need for all parts of the government to speak with one voice.

"So to all members of Congress of both parties, I ask you to take this vote for our national security," Obama said. "Today I'm asking Congress to send a message to the world that we are ready to move forward together as one nation."

Obama on Saturday sent a draft of the resolution authorizing him to use force against Syria. "Unified action by the legislative and executive branches will send a clear signal of American resolve," the draft resolution said.

Ultimately, the president's decision gives him political "cover" should he decide to abandon plans to attack Syria, because he is unlikely to flout a vote in Congress, said Ross Baker, a congressional scholar at Rutgers University in New Brunswick, N.J.

"They asked for it, he gave it to them and they turned it down, I don't want to defy the will of Congress," Baker said in predicting Obama's reasoning.

Even though they welcomed the president's decision to seek authorization for a strike, most Democrats and Republicans didn't endorse military action.

"Authorization for the use of force in this case should be contingent on the president setting clear military objectives that can meet articulated policy goals, including degrading any party's ability to use these weapons again," Rep. Buck McKeon, a California Republican and chairman of the House Armed Services Committee, said in a statement. "The coming days will determine if such a military operation can be identified."

Republican Senators John McCain of Arizona and Lindsey Graham of South Carolina are the only lawmakers so far who said that they wouldn't support a limited strike on Syria.

"We cannot in good conscience support isolated military strikes in Syria that are not part of an overall strategy that can change the momentum on the battlefield, achieve the President's stated goal of [Syrian President Bashar] Assad's removal from power, and bring an end to this conflict," the two said in a statement.

Divisions among Obama's own party also surfaced, with the two top congressional Democrats, Senate Majority Leader Harry Reid and House Democratic Leader Nancy Pelosi of California backing a limited strike. Reid of Nevada said the Senate will start holding hearings on the issue next week, adding that a vote on authorizing a strike will come "no later than the week of Sept. 9."

Other Democrats warned against an immediate strike.

Sen. Carl Levin, chairman of the Senate Armed Services Committee and a Michigan Democrat, reiterated his call to arm some in the Syrian opposition.

"I have again urged the president to use this time to help the Syrian people defend themselves by assisting vetted elements of the Syrian opposition in obtaining more effective weapons such as anti-tank weapons," he said in a statement.

Others such as Dick Durbin of Illinois, the Senate's No. 2 Democrat, cited the emotional and financial toll the Iraq and Afghanistan wars have taken on the U.S.

"If we can do something to discourage Assad and others like him from using chemical weapons without engaging in a war and without making a long-term military commitment of the United States, I'm open to that debate," Durbin said in a statement.

"After over a decade of war in the Middle East, there needs to be compelling evidence that there is an imminent threat to the security of the American people or our allies before any military action is taken," West Virginia Sen. Joe Manchin, D, said in an Aug. 30 statement. "I do not believe that this situation meets that threshold," he said.

Numerous Republican and Democratic leaders, including Levin and Senate Minority Leader Mitch McConnell, a Kentucky Republican, were calling on Obama to further consult Congress before launching any new military operation.

"When people like Levin are asking for time or for the president to consider getting an authorization, it's significant," Baker said.

Even so, Obama was within his executive powers to pursue a strike absent congressional approval, said Rep. Peter King, a New York Republican.

"President Obama is abdicating his responsibility as commander-in-chief and undermining the authority of future presidents," King, a member of the House Select Committee on Intelligence, said in a statement Saturday. "The president does not need Congress to authorize a strike on Syria."

Congress never sought to force Obama to seek an authorization vote, and Obama himself changed his mind on the need for a congressional vote only yesterday, according to a senior administration official who spoke on condition of anonymity.

One factor in his decision was watching U.K. Prime Minister David Cameron lose a vote on the use of force in the House of Commons, the official said. Obama told his chief of staff, Denis McDonough, that instead of hiding from the debate on Congress's role, they should embrace it, because it would strengthen his hand should the U.S. decide to attack.

The decision has another benefit, senior administration officials said: It would put Congress on the record in the decision and make it harder for lawmakers to criticize Obama's handling of the matter as many Republicans have been doing.

At the same time, it may box in Obama politically, if the House or the Senate votes no, analysts said.

Both President George W. Bush and his father sought congressional approval for military actions the younger Bush for Iraq and Afghanistan, and the elder for the first Persian Gulf War. All three times, Congress supported the use of force.

There are many reasons why Obama may fail in winning congressional approval, said Stuart Rothenberg, editor of the nonpartisan Rothenberg Political Report in Washington.

In addition to significant public distaste for any further overseas military commitments, Obama faces vast pockets of opposition in both parties, he said.

"This is one of those odd issues where there is a coalition of opponents that includes liberal Democrats and the more Tea Party, libertarian kind of Republicans who raise the specter of Iraq and executive powers," he said. "The president has a lot of work to do."

Time is also working against the administration.

"The further along you go from the actual act itself, the more people come up with excuses and other issues pop up," Rothenberg said. "From the White House's point of view, generally, you want to act right away."

Obama's decision to give members of Congress just what they were asking for is "very mischievous" because many of those same lawmakers are now in a political bind, Baker said.

"Members of Congress would prefer to be the hang back and be critical," said Baker.