In this case, I don't think it would be legal even if it normally is. Doing it in this case would be retaliation for a protected action. The National Labor Rel

In this case, I don't think it would be legal even if it normally is. Doing it in this case would be retaliation for a protected action. The National Labor Relations Act ensures the right to organize unions, and changing pay as a result of union-related activity would be illegal retaliation. This is similar to how an at-will employee can be fired for any reason _except_ for a protected class, like their race / gender / religion, etc.