Oversight and self-protection
The resignation of yet another member of Parliament for violating the code of ethics underscores the need for the political system to take action so that it can, basically, protect itself.
Such phenomena are damaging because they strike a chord and anger citizens. They also serve as a warning to political parties, which need to be more stringent about screening their candidates.
It is certainly positive that there was a resignation instead of a cover-up, but the damage has been done. That is why there must be no more such cases in the future.