I believe he is thinking of the, "at will" clause for employment in Michigan, as well as many other states. It basically means that an employer may terminate employment for any reason, as the employee works "at will" for the employer.
The only exception to the rule is if the discharge or demotion is a retalitory action (e.g. Insisting on a safe workplace), or based off of discrimination.
In my case, I do not think that it applies, as I am part of a collective bargining unit, the UFCW (Union).

