In an interview with Rolling Stone, Waters says that, although he cannot vote in the U.S., he supports Sanders:
He’s the only person in the race that I see with any credibility. He seems to speak the truth, far as one can tell at this point. He seems prepared to stand up against big money and the banks and stand up for the predicaments of minorities, the middle class and the working class in this country…When he speaks the truth, he sounds very left-wing, but that is because we have been fed this right-wing bullshit by the whole of the mainstream media since the Second World War. And it has gotten worse and worse and worse, and the outlets for dissenting voices have become fewer and fewer. So he is bound to sound out of step, because he is! And that is what is so good about him.
However, Clinton worries him:
Hillary worries me. I have an awful worry that she might become the first woman president to drop a fucking nuclear bomb on somebody. There is something scarily hawkish about her, and she has that politician look down of, ‘You are never going to get a word of truth out of me.’