Paul Krugman argues that there are lots of similarities between Trumpism and Republican ideology. The major difference is that the man at the top is better than most Republicans at convincing its less affluent base that he really cares about them. They believe that he is honest despite his history of lying about almost everything. They confuse honesty with "telling it like it is". In other words, Trump is honest because he does not hesitate to utter things that respectable elites are afraid to say. For example, he defended Bill O'Reilly who has been accused of sexual harassment by several women who worked with him at Fox News. That proves that he is really "one of the guys". Trump and Fox News have been making it more comfortable for people to express ugly things. Political correctness is an elite kind of thing. It has become part of their populist creed.
One of the differences between Trumpism and Republicanism is that Trump is an inept manager. His ideas about almost everything are fleeting. Its hard for his team to figure out what they should be doing. For example, he claimed that he would not get involved in things that did not directly affect America. He avoided moralizing about the use of chemical weapons against civilians after Assad used nerve gas on innocent civilians. Then he decided that killing innocent citizens should be punished and he ordered the military to use missiles against Assad. He could hardly wait to puff up his chest and boast that Obama had decided not to attack Assad after he warned him against crossing the "red line". Trump was not going to be a weak leader. What Trump did not think about was how the attack fits into his foreign policy strategy. That is because he does not have a strategy. He prefers to operate on impulse. That is one of the reasons why his healthcare bill did not become law when he only needed to sell it to his own political party. Trump's approach to tax policy is pure Republicanism. He wants to cut taxes for the rich and pay for the tax cuts by reducing spending on social welfare programs. His inability to pass his healthcare bill, which seriously cut federal spending, is creating problems for the tax changes that he has promised to the affluent part of the GOP base.
Its hard to figure out what comes next with Trumpism. However, we can bet that the world be an uglier place when he has finished messing everything up.