There was almost certainly something that was being unfairly held against him at work, whether that was his politics (a very credible explanation) or something else (for example, I once took the approach to this that part of what got him shunted to the side was him as a young father having sought a less stressful role at work so he could be home more, which in the 70′s for a man would have been… Not A Thing). But politics – and his refusal to prop up injustices – had to have played at least a significant part.

When you look at Arthur’s situation, you sort of have to figure one of three things: 1) He couldn’t do better at work due to lack of competence or the like; 2) He didn’t want to do better (because it was his dream job); or 3) Something just like @warriorlid14 suggested.

#1 really doesn’t have canon support. Arthur’s an amazingly three dimensional character, despite the fact that he often gets remembered as this meek little goof who’s sort of YesMollyDearing his way through life (a perception that seems to be bolstered by the fact that he’s constantly mispronouncing things and lacks understanding of even basic Muggle concepts – which has its own theories that I won’t get into, but it’s inconsistent with other canon evidence that suggests he is smart as a whip).

He’s curious (which I think is always a mark of intelligence) and good at what he does (he got Bagman out of a scrape, and Amos Diggory contacted him to help Moody out of a jam, saying Arthur was the only one who could). He knows who’s who in the Ministry and pays attention to what’s going on politically even if he doesn’t play the game [as much as others]. He’s authored legislation (”There’s a loophole in the law, you’ll find… as long as he wasn’t intending to fly the car…” “Arthur Weasley, you made sure there was a loophole when you wrote that law!” – CoS ch 3). He’s perceptive (he knew all along that the trio were not in the back room of the twins’ shop during the outing at Diagon Alley when they followed Draco in HBP, and in response to Harry’s expression of surprise, Arthur says, “Harry, please. You’re talking to the man who raised Fred and George.”) He’s good enough to be in the Order of the Phoenix. I could go on.

#2… Well, frankly, I’m incredibly dissatisfied with an Arthur who would knowingly let his kids go without just so he can do something that’s personally satisfying to him, and I don’t think he would do that, and I don’t think the canon evidence supports that, either. I think Molly’s overbearingness can make it appear, by contrast, that Arthur is checked out as a parent, but he’s really not. He has more than one conversation with Harry (like I pointed out above) where he’s very tuned in to the fact that Harry, Ron, and Hermione are prone to fucking around and getting into trouble (the only reason we don’t see such conversations between Arthur and any of his own kids is because it’s all Harry’s POV). He does take a backseat to Molly as disciplinarian, but that can be put down to individual temperament and parenting philosophy. Arthur is not about controlling his kids’ every move, but he will go through the roof when they do something he finds truly unacceptable (the Ton-Tongue Toffee with Dudley, or the twins trying to get Ron to make the Unbreakable Vow). He’s certainly not perfect, and there are things about him as a parent and a person that should, in fairness, be viewed critically (just as for every character or person), but if you pay attention to Arthur throughout the books, I think the idea that he’s sort of blithely kissed off his duties as a parent and provider is pretty laughable.

#3 makes sense and is consistent not only with what we know of the politics of wizarding Britain, but with the way things happen in real life all the time. It’s just not always that apparent to people who don’t look at things critically, who don’t know the full story, or who see things in black and white. (For example, part of my understanding and interpretation of Percy’s developing resentment towards Arthur is that, among a whole host of other thoughts and feelings swirling in Percy’s head, he probably looked at Arthur and truly believed, or convinced himself, that Arthur couldn’t be bothered to do better in life to support the 7 kids he decided to have. And I love Percy, and I don’t fault him for thinking or feeling that, from his vantage point at the time. To feel that your parent is repeatedly failing you is absolutely crushing, and this is a complicated parent-child issue.)

#3 is probably a very complex mix of reasons and things that have happened throughout Arthur’s life and career. His Muggle fascination. His personal politics and social views. The fact that he’s actually a bit of a hothead where either personal pride (duking it out with Lucius in the bookstore) or social justice (telling Albert Runcorn exactly what he thinks of him in DH) are involved. Oh, he’s definitely not perfect. Should he have been fucking around bewitching that car at home? Eh, probably not. But he’s not an idiot or a fool, and the man who hugs Percy without question in DH, after what they’ve gone through (especially when you consider Arthur’s pride rivals any of his kids’), is the furthest thing from a guy who doesn’t care enough about his family.

(Back to OC’s original point, Weasleys rock, and for the life of me I’ll never understand why people overlook the fact that Ron was standing up against discrimination at the age of 12 – something most adults can’t or won’t even do. But I had to pop off about Arthur for a bit after @warriorlid14‘s contribution!)