There are important differences between the cases of Peter Hain and those of Gordon Brown's deputy, Harriet Harman, and Labour's Scottish leader, Wendy Alexander, who are still awaiting the verdicts of the Electoral Commission.
The most obvious difference is scale. Peter Hain failed to declare over £100,000 whereas Harriet Harman's deputy leadership campaign accepted a much smaller sum, £5000, from a proxy for David Abrahams and Wendy Alexander accepted just £950 from a Jersey-based businessman who was not a "permissible donor".
Hain was regarded within the Electoral Commission as holding the law in contempt when he said he'd not met his obligations because he was too busy being a minister at the time and had left his declarations to his campaign staff.
Harman, in contrast, said she took the money in "good faith" and couldn't have known the original source. If the Commission accept this she will be cleared although she could face criticism for making insufficient checks on donations.
Alexander originally admitted to breaking the law and would, therefore, appear to be in a very similar position to Hain. Indeed the SNP are now saying that, like Hain, she should resign. However, after she studied her campaign paperwork, Labour's Scottish leader changed her story and said she did not knowingly break the law as she had accepted assurances from her campaign that the donation was, in fact, permissible. If the Electoral Commission accepts her version of events then she will not face a police investigation though others might. The Commission's verdict is expected next week.