Last year, the Michigan director of Americans for Prosperity, the right-wing activist group, explained, “We fight these battles on taxes and regulation but really what we would like to see is to take the unions out at the knees so they don’t have the resources to fight these battles.” Republicans understand full well that Michigan leans Democratic, and the GOP has total power at the moment, so its best use of that power is to crush one of the largest bastions of support for the opposing party.
Obviously, one should always be suspicious of theories that attribute malicious will to power to the other side while absolving one’s own allies of the same. I don’t think Democrats abstain from this behavior (to anything like the degree the GOP employs it) because it’s made of angels. Rather, the Democratic party comprises an economically diverse coalition, including not just labor but business as well. Even if Democrats could come up with a plan to crush the political power of business — which is hard because business is way larger and stronger than labor, even in Michigan — huge chunks of the party would object. Whereas nobody in the GOP cares about labor at all, so it’s easier to unify them behind the kind of political/class war strategy we’re seeing here.