Washington, September 10 (RHC)-- The White House is asserting that U.S. President Barack Obama already has authority for the expanded military campaign against the Islamic State he has asked Congress to approve.

The message was delivered to lawmakers ahead of Obama’s address to the nation tonight. Obama is expected to outline his strategy for what the White House calls "degrading and ultimately destroying the terrorist group."

Leaked details forecast a long-term campaign that will extend U.S. airstrikes from Iraq to Syria, where ISIS has established a foothold battling Syrian President Bashar al-Assad. Obama’s calculations are said to include how to intervene without aiding the Syrian government.

Although Obama has asked Congress to vote on the authorization of force he says he already has, it’s unclear if enough lawmakers want the opportunity. Speaking to The New York Times, Republican Representative Jack Kingston, who supports an authorization vote, said: "A lot of people would like to stay on the sidelines and say: 'Just bomb the place and tell us about it later.'"