With support tanking in Congress for a US military strike on Syria, the big question is whether President Obama would go forward with an attack if Congress does not approve one.

The answer, according to one of his top national security advisers, is no - the president does not intend to go forward without Congress.

"The president, of course, has the authority to act, but it is neither his desire nor his intention to use that authority absent Congress backing him," Deputy National Security Adviser Tony Blinken told NPR's Steve Inskeep this morning.

Privately, other senior administration officials have been saying the same thing for days: Absent another major development in Syria, they find it inconceivable that the president would move forward with an attack if Congress fails to authorize it.

Credit: J. Scott Applewhite/AP Photo

When President Obama was asked about this on Wednesday at a press conference in Sweden, he said he retains the authority to act, but he said the Congressional vote was more than just symbolic.

"I did not take this to Congress just because it's an empty exercise," he said. "I think it's important to have Congress's support on it."

White House officials say the implications of a no vote go far beyond Syria. If Congress fails to approve this small targeted action, officials believe it would signal a significant pullback of US operations around the world including a quicker withdrawal of US forces in Afghanistan. It would also, officials say, effectively rule out any potential military action against Iran even if the Iranian government moves forward in developing nuclear weapons.