Once people vote and Johnson is on the Libertarian line, he will hurt Romney like all libertarians steal votes from Republicans.
Well, that goes against available statistics (in other words, you are pulling the idea Johnson is hurting Romney out of your ass). Plus, a lot of belief about where the third-party vote comes from is wrong; most people who vote third-party always do so, they aren't stolen from anywhere. I remember reading an article a few years ago -- unfortunately I can't find it now -- that actually said Ralph Nader
helped Al Gore in Florida, because he attracted environmentally conscious and far-left voters to the ballot box (otherwise they may have stayed home), where some amount probably realized Nader had no chance and voted Gore; this, the author said, explained exit polling which showed Bush winning Florida by a full percentage point if Nader wasn't on the ballot. But, then again, exit polling isn't famed for accuracy.