(NBCNC) - Pentagon sources tell NBC News the first time the U.S. could launch an attack is Thursday and it's shaping up like Libya did, as a multi-nation action.
President Obama worked the phones, lining up allies to help strike Syria.
Britain sounds on board, and the French say they're ready.
U.N. investigators have not finished their work in Syrian neighborhoods where hundreds of civilians died but President Obama no longer questions if chemical weapons were used.
"It's not around the question of whether the Syrian regime is responsible. It's around the question of what is the appropriate response," said White House Press Secretary Jay Carney.
The reported planned response is three days of strikes by cruise missiles.
Democratic Congressman Adam Schiff is a member of the House International Relations Committee.
"We can make this punishing - we can direct it to how they have carried out these attacks by degrading their missile capability their air capability," said Schiff.
Four U.S. destroyers are ready in the Mediterranean.
They're based in Norfolk whose congressman is upset.
"I really believe its unconstitutional," said congressman Scott Rigell a republican from Virginia.
Rigell wants president Obama call a joint session of congress to get authorization, but fears he won't.
"This is not right! It's not a democratic issue or a republican issue," Rigell said.