The White House is ready to share with lawmakers Tuesday its plan to seek authority for the use of military force against the Islamic State group, setting up the first war vote in Congress in 13 years.

Presidential counsel Neil Eggleston was set to address the Senate Democrats’ luncheon the day before President Barack Obama is expected to formally unveil his proposed authorization, a Democratic official revealed.

The White House and proponents of a new authorization for use of military force argue that passage is important to show unity in the fight against militants who have seized territory in Iraq and neighboring Syria, imposed a violent form of Sharia law and killed U.S. and allied hostages.

To get congressional approval, Obama must find a balance between lawmakers who want wide authority to fight the Islamic State group and others, including members of his own party, who worry that a new authorization to use military force will lead to another American entanglement in a prolonged war.

So far, no formal language has been submitted, although the White House has completed a draft, according to a senior congressional official who spoke only on grounds of anonymity because this person wasn’t authorized to discuss by name a strategy being discussed privately.

Report complied with information from The Associated Press