Coons said in addition to authorizing Obama's unconstitutional Authorization for Use of Military Force (AUMF) Congress must levy a new tax on Americans to pay for military action against IS

The US has spent more than $5 billion on the war against IS since August, 2014.

"The daily tab for fighting ISIS had already climbed more than 20 percent between May 21 and October 15 of this year, from $9.1 million a day to nearly $11 million, according to the Pentagon's latest public figures," reports Vocative. "More than half of those costs came in the form of airstrikes, which the U.S. has employed since August of 2014 to pound Islamic State targets. Munitions, logistics and operational support accounted for the remaining costs, the Pentagon said."

The cost is expected to rise considerably now that the Obama administration has said it will step-up the campaign to wipe out the group.

Despite spending billions the air campaign has failed to weaken the Islamic State, according to intelligence officials.

"We've seen no meaningful degradation in their numbers," a defense official told the Associated Press. He cited intelligence estimates that put the Islamic State's total strength at between 20,000 and 30,000, virtually the same number as last August when the airstrikes began.

On Monday Rep. Pete King, a New York Republican who serves as the Chairman of the House Committee on Homeland Security, said "that after 15 months of,16 months of air attacks by the U.S., it's had really minimal impact on ISIS."

"ISIS, I believe, is stronger than it was 16 months ago. They certainly have a larger land mass under their control. …There's no doubt ISIS is planning increased attacks against the US."