The voting is built into the bitcoin protocol-- the miners that find the next block are voting for the piece of software they are running. If there is a schism and some miners are running other software then two chains could -- COULD -- emerge-- but one will rapidly become the dominant one. ( for a period the two chains will effectively double everyone's bitcoins, but the losing chains coins will rapidly lose value as hashing power switches to the dominant chain.)

This could be chaotic so the debate is really how to avoid two co-existing chains in hard fork situation.

But bitcoin itself is, every 10 minutes, voting for what the "right" chain is, which is defined as the longest.

Right now today if you're mining on a block and find out that there is a longer chain, the node switches.