“Pledges” like these are stupid. They are meaningless and will only serve to make those that sign look like they support something they don’t. They aren’t laws or regulations. What is the point?
I think a lot of them are well-meaning, but they're all too often thrust in the faces of candidates by some single issue group, who essentially demand that the candidate "SIGN THIS!", or be demonized by them.
I'd prefer for every candidate to simply be clear enough about where they stand on a range of issues, that they can't be forced to sign these pledges at all.