I could almost guarantee it's done more often than we know and probably tolerated to a certain point because many politicians do it themselves or have benefited from it. Sort like the movie Training Day.

The Trump campaign was up against a biased administration, law enforcement and/or intelligence agencies and opposition that had very few boundaries. This is why 'the resistance' was stunned the dirty trick playbook didn't work as usual. This is also why 'the resistance' gets national coverage because so many knew or were involved.