I found the movie at http://www.comingsoon.net/films.php?id=4680 . Scroll down until you find Clip 4 - 'Complete Dolphin Opening "Thanks for the Fish Song"'. Below that is the video that Zaphod used during the election. 
"You need me. You wouldn't be much of a hero without a villain. And you do love being the hero, don't you. The cheering children, the swooning women, you love it so much, it's made you my most reliable accomplice." -- Lex Luthor to Superman, Question Authority, Justice League Unlimited
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