Two obvious questions

Maurice Williamson was sacked within the space of 2 hours this morning after the Herald revealed he had attempted to interfere in a police investigation on behalf of a party donor. Its exactly what should happen when a Minister behaves corruptly and pisses on our constitutional norms like this. At the same time, it raises an obvious question: why hasn't Judith Collins suffered the same fate? Or is corrupt behaviour only punished when it involves older Ministers the PM would like to dispose of?

And then there's this bit:

In a statement, Prime Minister John Key says he's accepted Mr Williamson's resignation.

"I have been made aware that Mr Williamson contacted Police some time ago regarding their investigation of Mr Donghua Liu," Mr Key said.

Which raises the other obvious question: why didn't Key sack him then? There's absolutely no legitimate reason for a Minister to contact police in this way, and Williamson's "excuse" that he wasn't trying to influence the investigation doesn't wash (why else would he contact them? And doesn't he understand that by doing so, he has exerted influence?). Or is corrupt behaviour only punished if it becomes public? And if so, how many other current Ministers have committed similar offences, but are still in their jobs because we don't know about them?