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Ministry: Misuse of Muggle Artifacts Office
Mr. Weasley is a model of a steady, dependable father. As a father, Mr. Weasley is very protective of his children, and of Harry too. When Harry is leaving the Dursleys for the year, Mr. Weasley asks indignantly: "You aren't going to see your nephew till next summer [...] Surely you're going to say good-bye?" (4.88). And when Fred and George slip Dudley Dursley a Ton-Tongue Toffee, Mr. Weasley does his best to scold them without telling Mrs. Weasley what has happened. He knows that she will really blow a gasket. So he tries to keep the peace.
Professionally speaking, Mr. Weasley is a relatively low-level Ministry employee in the Misuse of Muggle Artifacts Office. It's thanks to Mr. Weasley working his Ministry connections that he can bring his children – plus Harry and Hermione – to the Quidditch World Cup. Mr. Weasley gets a lot of guff in wizarding society for being (a) poor, and (b) for really, really liking Muggles things. He finds Muggles as interesting as we find wizards (though he doesn't seem to have much of a grasp on Muggle technology). Here's one example of the kind of exchange Mr. Weasley often has about Muggle stuff:
"They've got an electric fire," Harry explained.
"Really?" said Mr. Weasley excitedly. "Eclectic, you say? With a plug? Gracious, I must see that ..." (4.41)
Now, of course, we can compare Mr. Weasley's interest in Muggle things with the kind of bigoted nonsense that people like Draco Malfoy spew. Mr. Weasley is a pureblood wizard, but he doesn't assume that wizards born to wizarding parents are any better than wizards born to Muggle parents. In the wizarding world, Mr. Weasley is quite the liberal.
Even though Mr. Weasley is a hardworking, honest Ministry employee, his low pay and low social status give his many children some problems at school. Ron has to contend with second-hand clothes and has to defend his father's reputation against the snottiness of Draco Malfoy, saying, "Dad could've got a promotion at any time ... he just likes it where he is ..." (11.113). When Rita Skeeter publishes a nasty article about "Arnold" Weasley (rather than Arthur), Draco Malfoy sniffs, "Imagine them not even getting his name right, Weasley. It's almost as though he's a complete nonentity, isn't it?" (13.83). The social struggles of the Weasley family, and of Mr. Weasley in particular, show that it's not what you know, it's who you know that will get you ahead in the wizarding world. Sigh.