Republicans are willing to look away, and let Trump run rampant, if it means that they'll get their part in return (judges, etc.)
Trump, in turn, will say anything. He has no restrains, and knows this - he can say absolutely anything, and no-one within will do or say anything.
Right now, the presidency (for Trump) is a case of survival. He needs to remain in power, in order to escape whatever civil charges he'll face.
For his own sake, Trump should have never ran for Presidency. He hates his job, and got lost in his own ego.
He really does understand the base, the media and pollsters, and other the other candidates never really got that in the last election.
A LOT of politicians are willing to lie and fan those flames, but he has been more successful at knowing what lies to tell and really breaking new ground with his bullshit.
Does anyone think that a conspiracy theory invented by Rick Perry or Mitch McConnell would go viral or catch the public eye like one of Trumps half assed tweets?