Remember the good old days, when there were such things as Reagan democrats? I'd like to see something like that return today.
Sure, most of the union leadership is hopelessly corrupt and greedy. There is no reaching them. And as you said, you probably wouldn't want them on your side anyway.
But many rank-and-file union members would be conservative if they just thought about it for a moment. Those folks want a safe neighborhood for their kids to grow up in. They support a strong military. and they don't like paying high taxes to support welfare bums.
Oh, and they are no fan of unrestricted immigration.
The GOP has lost the propaganda war with regards to the union rank-and-file. It is worth trying to get * some * of those votes back.
One more election cycle like 2008-2012 and this country is done.