I Believe In (Insert Name Here)

I can not help but look up at the pictures in the top part of the MyLot political page. Up their show a picture from the movie Milk. In the picture it says I believe in Harvey Milk, well at lest that is what I thing it says. This is not the first nor will it be the last time I have heard or seen that phrase. Is it just me or does that phrase not make any sense. If I was to say I believe in Barack Obama that would be true, last time I checked BHO does exist. Now if someone wanted to run a political campaign on the slogan I believe in Santa and the Tooth Fairy, well now that would be different. I guess my question is how is the slogan I believe in (Insert Name Here) a winning slogan?