The Chicago Teachers Union is demanding an annual pay raise of 9% or the consumer price index-whichever is less—and won't rule out a strike, even with one of their own in the mayor's office, union president Stacy Davis Gates said Thursday.

"We're a labor union. We're not a political party Leven though] people...want to redefine the Chicago Teachers Union in all types of ways," Davis Gates told the Sun-Times.