The Voice doesn't have "judges," only coaches. The coaches help and advise the members of their team. Contestants are first eliminated in battle rounds, where two people go against one another. The coach picks which person to keep on their team, and who gets eliminated. Once they get down to like, 12 contestants, they start the live shows, where votes and purchases on iTunes save the contestants, until there is only one person left.
tl;dr, The Voice only has coaches, America is "the judge."