The problem is that you are equating two things which are NOT equal.
1. The "Ron Paul" campaign is a NATIONAL election -- one that is tied up more with people's "emotional" feelings about what "direction" the country will take.
2. The Sabrin campaign is for a STATEWIDE election -- which people pay significantly LESS attention to, is more about "getting stuff for their state" (bringing home the pork), and which therefore *IS* shaped and significantly impacted by signs.
And BTW, for LOCAL offices (county supervisor, etc.) campaigning is ALL ABOUT how many signs -- and the "image" projected by the sign's design/colors, etc.
So far from doing nothing, signs (and bumper stickers & buttons) ARE important. Just NOT for the campaign you thought, or in the way you thought.