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.

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.