How is it that cake became a favorite platform for American political debate?

It really should be a piece of cake. Customer comes in, asks for a cake with a specific design or for a particular event, baker makes it, everyone's happy.

But sometimes customers and bakers have clashed over what goes on the cake, or whether to make it at all. An Oregon bakery was fined for refusing to bake a cake for a lesbian couple's wedding. A baker in Colorado refused to write anti-gay messages on a customer's cake. A Louisiana man posted a video lambasting a Wal-Mart for not making a cake with a Confederate flag on it.

Somehow, cake can raise questions over where the free speech of customers ends and that of bakers begins.