Uh, not necessarily. If the left-turner was already in the intersection ( delayed because of cars ahead of him, for example ) as the light turned red, most state would allow him to complete the turn on red without penalty.

The OP doesn't say, but if that's the case, it could very well be a situation of shared responsibility. The OP should have noted that the car was in that position, and not proceeded across the intersection until the car was all the way through. Having the green light does not absolve you of the responsibility of ensuring you're not contributing to a dangerous situation.

Edit: Found this on the web:

"the Oct-98 printed edition of the Illinois Driver's Manual "Rules Of The Road" says: "If you enter an intersection when the light is green, you may finish your turn even though the light turns red" (Chapter Three: Traffic Laws - Right-Of-Way)."

That being the case, the OP may very well be legally responsible for contributing to the accident if the car was already in the intersection.