This is one of the worst stories I've seen, at least as far as political bias:
This reminded me of the (excellent) book titled "The Armchair Economist" by Steven Landsburg. That book has a section titled "How to Read the News". It goes through examples of biased stories and how the exact same facts could be used to tell a different story. For example, let's try rewriting the above story with the opposite slant:
"For generations, Michigan forced employees in a union workforce to pay union dues - whether they wanted to be part of the union or not. A sizable portion of these dues, essentially a tax, funded political campaigns and large salaries for union bosses.
These restrictions were removed by Republicans in just hours, and if signed by the governor, Michigan workers will be taking more money home in their upcoming paychecks."
I like this version better, but I am libertarian leaning. Of course I'm not attempting to write an objective story. This version clearly has my opinion worked into the story, but I don't think it's any more biased than the quotes above.
The problem, of course, is that writers at the AP should be objective.