Unfortunately political systems are often held together with “tradition” and “gentleman’s agreements”, where conventions dictate how people should behave. Politicians typically followed them because it is seen as the honourable and right thing to do.

However, it seems to be a recent trend among the hard right that politicians just ignore those conventions because:

a) those conventions are inconvenient b) honour means nothing to them, and c) nothing actually enforces those unwritten rules - so there are no consequences for ignoring them

Similar things have happened here in the UK as well. I guess our political systems both assume some degree of good will & trust in its representatives, and it generally turns out that trust is misplaced.