"We knew Hillary served on the Walmart board. The company is notoriously anti-union. I think it basically goes without saying that she wasn't going to be pushing for a more union-friendly company policy, certainly not at a public board meeting, or else she wouldn't have stayed on the board for more than five minutes. The story points out that she did push for more representation of women in the higher ranks of the company and also for more green policies -- and on both counts had she at least some success."
I’ve had some experience with politics in major companies. It isn’t that you pick the fights you can win, it’s that you pick the fights that are fightable. In the case of Mrs. Clinton, had she gone to the wall on the anti-union stance, assuming that she wanted to, she would have destroyed her usefulness in the battles on other issues where she was able to make a difference. In my opinion she did exactly what was most effective for her ability to create useful change in the company's direction.
If you want to beat Senator Clinton up there are a number of issues you can use, but let go of this one. It just doesn’t work.