As you may know, Ichiro Ozawa, general political heavyweight in Japan, is now on trial for his office having accepted some 400 million yen in illegal campaign contributions, after his secretaries have been found guilty of the same. Opinions seem sharply divided if there was criminal intent; whether 400 million is a lot or not; and whether Ozawa knew about it or should shoulder any blame if he didn't.
If we want to get a sense of what is acceptable, it would certainly help to compare with other places. We're (not so) fortuitously right now getting a point of comparison in Swedish politics. Håkan Julholt is the recently elected leader of the largest opposition party. He has now been found to have received too much reimbursement for his working apartment.
A bit of background: House members in the Swedish parliament have a right to an allowance for a place to live in Stockholm if they don't live there already. The (quite reasonable) idea is that they represent their area in the country and shouldn't have to move away permanently to work as House members. On the other hand they do need to spend a substantial part of the year in the capital, which is an expensive place to live. So you get reimbursed for your share of any accommodation in Stockholm — the operative point here being "your share". Most members do not use this; they stay in accommodations provided by the House.
What Juholt has done for years is claim the entire rent on his apartment, while living there with his partner (they're not married, and I don't think the rules would be any different if they were). He should have been claiming only half. The total disclosed amount he has received improperly is 160 000 crowns, about 1,7 million yen. At this point there are people claiming he was informed this was improper, while he and his people say he was not. There is no publicly disclosed evidence either way.
So, 160k crowns — 1.7 million yen — in allowance he should not have received, knowingly or by mistake. As a result, the police and prosecutors have started a criminal investigation. Every newspaper (including those loyal to the opposition party) are combing through years of old receipts and documents to find more. Some party members are already publicly calling for him to step down. Everybody seems to agree that if he hasn't disclosed the total amount or lied in any other way; if there is credible evidence he was warned about this and went ahead anyway; or if the police investigation leads to charges being filed; then he is most certainly gone as party leader and most likely gone from national politics altogether. Even if nothing more surfaces it's an open question whether he can stay on and be an effective leader of his already wounded party.
Politics is a game of trust. Whether you actually do something wrong matters far less than the perception that you did. I'd give Juholt a 50% chance of political life after this, and that's given that nothing more happens. Similarly, whether Ozawa has done anything illegal or not is up to the courts to decide. But Unfairly or not he is already being judged by the media and the public, and ultimately that's what determines his fate. If you're playing a game of trust it doesn't matter if you're technically legal. The perception of you as upright and honest is the only thing that matters.