Regardless of what anyone says, Hermione Granger wouldn't get married just to obtain a proxy vote in the Wizengamot. After all, she's a war heroine and an honest and hard-working Ministry worker. People and papers shouldn't be allowed to go around insinuating that she'd exploit the sanctity of wizarding matrimony and the entire legal system simply for the sake of passing a few revolutionary pieces of legislation. Obviously, she eloped with former Death Eater Draco Malfoy because of her... hidden domestic side.