In Michigan, most employees are considered to be an at-will employee. The term at-will is thrown around and few really understand what it means. Most assume or use the term to mean that an employee is terminable at the whim of the employer. While there is truth to this idea, it hides the complete meaning and the history of the rule. The seminal case in Michigan is Toussaint v Blue Cross, 408 Mich 579 (1980). This case analyzed the relationship between the employer and the employee. The case is still - 30 years later - the most commonly cited case for at-will employment.

This case arose out of an employment relationship and was for a claim of retaliation under Title VII. The main issue on appeal was whether a voluntary demotion could be an adverse employment action sufficient to establish a claim. The court held that it could be. 

Hicks v. Forest Preserve District of Cook County, Illinois, (Dk. No. 11-1124) (7th Cir. 2012) (Decided April 18, 2012)

What makes it interesting is that the employee was not given a pay cut, just a different job.  The Court found that could still be an adverse employment action 
The case cite is below and you can read more after the break.  Holland v. Gee (Dk. No. 11-11659 & 11-11883) (11th Cir. 2012) (decided April 17, 2012 for publication) 

(h/t employmentlawblog.info)