If people have the right to vote, they have the right to NOT vote as well. I imagine most people who did not vote for Romney did not vote for Romney because they didn’t want to vote for Romney. It is counter to American ideals of liberty to try to bully someone into voting at all, let alone for the candidate YOU choose.
You want to win elections? Quit blaming the people who reject your candidates and start running candidates people won’t reject.
There ya go. If the customers aren't showing up, then your product sucks... Simple as that.