1. The institution shapes the person. The Presidency is, literally, an awesome institution, as is the White House. It will shape and temper Trump, as we saw already with his deferential and respectful meeting with the President there.
2. Governing, unlike running a business, requires compromise. Truman famously said of Eisenhower winning the presidency: "he'll sit here, and He'll say, 'Do this! Do that!' And nothing will happen. Poor Ike--it won't be a bit like the Army. He'll find it very frustrating." The same will be true for Trump, a business executive who, to say the least, is not experienced at compromise.
3. Bureaucracies, made up mostly of career civil servants, are slow-moving things, and can often stymie chief executives. Even during the Cuban Missile Crisis, JFK complained about how slowly things moved in the State and Defense Departments. It will be difficult for Trump to do much of anything quickly.
4. The Presidency is a tough job and a lot of work. Presidents are presented with thick daily briefing binders every day. Trump does not like to read.
5. Besides all of these other annoyances, Trump is likely to be bedeviled by numerous legal issues, unlike any past President. There are some 75 lawsuits pending against him right now, and he has been involved in some 3500 over the course of his career.
6. Trump has already achieved his principal goal--which was simply to win. He has never in his life ever exhibited any interest in helping other people: indeed, he did not contribute any of his own money even to his own charitable foundation, which was used mostly as a tax dodge. So what more does he have to prove, now that he has won the biggest prize in the world?
7. Managing the Presidency will be frustrating for Trump, a man who is impetuous, temperamental, imperious, and self centered. My guess is that he will not last four years in the White House. Either he will resign in frustration, turn over the management of the Presidency to Mike Pence, or be impeached.
So take heart, Democrats! Maybe all is not lost!