A US Airforce plane taxies on the runway after landing at the Incirlik airbase, southern Turkey, Saturday, Aug. 31, 2013. U.N. chemical weapons experts have left Syria and crossed into neighboring Lebanon. The team on Friday carried out a fourth and final day of inspection as they sought to determine precisely what happened in the Aug. 21 alleged chemical weapons attack near Damascus. The team took samples from victims for examination in laboratories in Europe.

WASHINGTON - Members of Congress, abruptly handed exactly the war powers many had demanded, grappled Saturday with whether to sign off on President Barack Obama's plan to punish Syria for an alleged chemical weapons attack. Now with a stake in the nation's global credibility, lawmakers were seeking more information about the possible consequences of striking a region without knowing what would happen next.

The debate over what action, if any, Congress might approve is in its infancy. But the first contours began emerging within hours of Obama's announcement.

Sen. John Cornyn, R-Texas, said he doesn't believe Syria should go unpunished for the Aug. 21 attack near Damascus. "But we need to understand what the whole scope of consequences is," he said by telephone. "What the president may perceive as limited ... won't stop there."

Arguing for a strategy that seeks to end Syrian President Bashar Assad's rule, Sens. John McCain of Arizona and Lindsey Graham of South Carolina issued a joint statement saying that any operation should be broader in scope than the "limited" scope Obama described.

"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 Assad's removal from power, and bring an end to this conflict, which is a growing threat to our national security interests," the senators said.

"Anything short of this would be an inadequate response to the crimes against humanity that Assad and his forces are committing. And it would send the wrong signal to America's friends and allies, the Syrian opposition, the Assad regime, Iran, and the world - all of whom are watching closely what actions America will take," they said.

Lawmakers of both parties had, for days, demanded that Obama seek congressional authorization under the War Powers Act. Until Saturday, the president showed no willingness to do so and the military strike appeared imminent. Then, from the White House Rose Garden, Obama said he would strike Syria in a limited way and without boots on the ground. But, he added, he would seek congressional approval first.

"All of us should be accountable as we move forward, and that can only be accomplished with a vote," Obama said. "And in doing so, I ask you, members of Congress, to consider that some things are more important than partisan differences or the politics of the moment."

With that, Obama dropped the question of Syria, the nation's credibility and the balance of government power in the very laps of lawmakers who had complained about his go-it-alone-style -- but were less clear about how they would want to deal with a horrific chemical attack that the administration said killed 1,429 people, including 426 children. Other estimates of the death toll were in the hundreds.

There's little doubt that Obama as commander in chief could retaliate against Syrian targets without approval from the American people or their representatives in Congress. He did it two years ago in Libya, but in that case, the U.S. led a NATO coalition.

Congress' constitutional power to declare war was refined and expanded by the 1973 War Powers Act, which requires a president to notify Congress within 48 hours of initiating military action and bars U.S. armed forces for fighting for more than a maximum of 90 days without congressional approval. President Richard Nixon vetoed that bill, but Congress overrode the veto.

Even with that power, Congress hasn't formally declared war since World War II.

Every subsequent conflict involving U.S. forces, including military conflicts in Korea, Vietnam, Panama, Iraq, the Caribbean island of Grenada, Kosovo and Libya were undeclared, even though in most cases Congress did vote approval short of a war declaration -- sometimes after the fact. The Korean War was fought under the auspices of the United Nations, the one in Kosovo, by NATO.

With Syria, Israel's safety was a key concern. Dealing a blow to Iranian-backed Syria could mean a retaliatory strike against a key ally staunchly backed by many lawmakers, and some said that any president would need the weight of Congress behind him in such a situation.

"The potential for escalation in this situation is so great that I think it's essential that the president not be out there on his own," Rep. Mac Thornberry, R-Texas, said Saturday in an interview.

But that's a different question than whether to carry out such a strike. Like Cornyn, Thornberry said he wanted to know what the goals would be-- and the consequences. In town halls held over the recess, he said, constituents asked him why what happened in Syria should matter to them.

"The president has to convince us," Thornberry said.

What to do about Syria is a politically perilous question for lawmakers, and one that has scrambled loyalties. Still uncomfortably fresh is the memory of the Iraq war and the Bush administration's justification -- since disproven -- that Saddam Hussein's government possessed weapons of mass destruction.

Liberals who voted in October 2002 against giving Republican President George W. Bush the broad authority to invade Iraq over weapons of mass destruction are echoing Obama's push for punitive strikes against Syria.

Republicans who in the past embraced Bush's military doctrine of pre-emptive action -- and repeatedly rejected Democratic attempts to end decade-plus conflicts in Iraq and Afghanistan -- have rhetorically grabbed 1960s peace signs in warning against the implications of U.S. intervention in the Mideast conflict.

If Obama intended to make the debate less about his leadership and more about the policy, the move to seek authorization didn't work on Rep. Peter King.

King, a New York Republican and a member of the House's intelligence committee, suggested that the president was undermining the authorities of future presidents and seeking a political shield for himself by going through Congress.

"The president doesn't need 535 members of Congress to enforce his own red line," King said.