To the extent that there is an intellectually coherent case for Trump, as opposed to nostalgia or blind rage about social change, it revolves around his claim to be a brilliantly successful businessman. Reasonable people can disagree about whether Trump is, in fact, a tremendous success, and about whether running a business is a fair analogy to running a government (I have doubts about the former, and would adamantly deny the latter). What is not open to debate, however, is that his particular businesses in no way resemble the federal government.
Trump basically does two things: build and operate high rise buildings and resorts; and sell his name as a brand. His companies are run by himself and his family; as a result, he can change course and make deals at a moment’s notice, without taking input or considering the interests of people outside his inner circle. That suits his erratic method of decisionmaking perfectly.
The federal government is not like that. It makes millions of decisions affecting the interests of the entire nation every day. It is subject to procedural rules that are intended to guarantee fairness at the expense of speed. Changing its course is a difficult process. Comparing it to Trump’s organization is like comparing a speedboat to the Queen Mary 2.
Trump isn’t interested in the nuts and bolts of governing; he just wants to jet around the world, be the country’s dealmaker-in-chief, and get on TV every night. In other words, he would try to run the nation the way he runs his companies. Since that can’t possibly work, the actual task of governing would probably fall to Mike Pence, because, in the final analysis, someone has to do it.