I don't think we should normalize a President accusing, without any evidence, the previous president of wiretapping him... over Twitter.
That's one example of something that should never be normalized.
It should be comforting, though, that so far they have always turned eventually - as the evidence for Watergate became overwhelming, the public made it clear there were some lines that could not be crossed. I suspect we will see something similar with Trump once it becomes clear that things are not going to get materially better for the people who voted for him, but it may take several years and possibly a second term. In the meantime, those of us see just how shitty & insane the Trump administration is will have to be content to be Cassandra.
[1] https://en.wikipedia.org/wiki/United_States_presidential_ele...
[2] https://en.wikipedia.org/wiki/Watergate_scandal
[3] https://www.nytimes.com/2016/12/31/opinion/sunday/nixons-vie...
[4] https://en.wikipedia.org/wiki/Warren_G._Harding
Nixon did not really do anything that previous presidents hadn't done. Those lines had already been crossed plenty of times. See It Didn't Start With Watergate -- https://archive.org/details/LaskyVictorItDidntStartWithWater... Or read Robert Caro's biography of Lyndon Johson and read about all the blatantly illegal things Johnson did. Also -- the flip side of the Nixon story is that the FBI and perhaps CIA almost certainly got away with breaking the law and illegal wire taps -- https://www.stratfor.com/weekly/death-deep-throat-and-crisis... Should we be comforted if the unelected branches of government can break the law to expose the elected branches?