Everyone wants to know what a president Trump would actually do. I think the only surprise would be if Trump governed mundanely for four years, not surprising the whole country -- supporters and opponents -- several times. However, there are some issues that have more urgency than others, so they will be the ones we are most likely to see action on relatively soon.
(a) Supreme Court vacancy: Highly placed Republicans have decided that Trump will safely nominate a conservative to replace Scalia. If he doesn't, I expect Republicans to begin looking for ways to impeach him soon thereafter. This is absolutely the main thing that got the support of many Republicans, and it would be a surprise if he changed directions immediately. (It also makes me sad that the most important thing about the president is that he gets to appoint Supreme Court justices, but that's another matter.)
(b) Appointing a special prosecutor to investigate Hillary Clinton: I had forgotten that Trump said he was going to do this until I read about it today. You can add this concern to Clinton's already deep frustration about losing the election. I am one of those who thinks that she clearly broke the law (as well as going against the advice of her own people) in setting up a private email server. I strongly believe that justice should be applied equally to the wealthy and powerful as well as to the weak. Nevertheless, I really hope Trump does not take this step. It reminds me too much of the late Roman Republic. Those in public office were immune from prosecution, but as soon as their positions expired, they were likely to be brought up on some charge or other. The predictable result was that no one wanted to give up office for fear of facing endless court cases, so they held office longer and eventually destroyed the Republic. We're a long way from ancient Rome, and I do feel that in this case a prosecution would be entirely justified. The long-term precedent, however, is just too troubling for me. (Consider that, of the last three presidents, Clinton was impeached, and there were serious discussions in Congress for impeaching both Bush and Obama.) If the prosecutor is appointed (as I fear he will be), I hope he will pusue minimal penalties, such as loss of her security clearance and maybe her pension. (Does she even get a pension? I don't know, I assume so but I could be wrong.) Jail time would be a serious mistake. (Here's a brilliant idea I just read about: Trump should pardon Clinton. It keeps alive the idea that she did something that at least deserves investigation, while showing him to be more magnanimous than most people would expect. I almost wonder if Clinton would decline the pardon on the grounds that she doesn't need it, and whether Trump would then appoint a special prosecutor...)
(c) Repealing ObamaCare: This law, and Trump's promise to get rid of it, are undoubtedly important reasons for his electoral victory. Republicans have voted several times for repeal in the last 6 years, only to be vetoed repeatedly. Since they have control of Congress now, it should be a simple matter, right? Actually, I doubt it. What could be simpler than closing Guantanamo Bay, something that Obama could have done without even a new law? And yet, 8 years later, it is still open and his promise is unfulfilled. The PPACA is a huge law with a vast bureaucracy already. It has taken years for it to get ramped up to full implementation, and trying to get rid of it all at once would cause serious dislocation. I hope they vote to get rid of it, but I hope they don't do so in such a way as to cause a lot of issues for insurers and insureds. (I'm sure in the long run, it will be easier on all of them, I just want to make sure the repeal makes it to the long run.) Apparently alone in the world of political commentary, I value continuity strongly. People count on it to make decisions. Ripping a tumour out of a patient's body too quickly can be as harmful as the tumour itself, so I hope Congress and the president take their time with this operation. I should also point out that Republicans are not close to a veto-proof majority in the Senate, so they may still have serious difficulties enacting repeal.
(d) Erecting The Wall: This is Trump's signature campaign promise, and it will be substantially more difficult to implement than removing ObamaCare, and maybe even than implementing ObamaCare. That's a huge border, folks. I don't think the Mexicans are going to pay for it willingly, and even if Trump can get money for it, there are still enormous obstacles to overcome. I would be amazed if there were much more than a plan to build a wall at the end of Trump's first term. Maybe a few sections of the wall in especially vulnerable areas (or areas where building it would be technically feasible and not too expensive).
(e) Repealing international trade agreements such as NAFTA and the TPP: Compared to some of the other items, these would be relatively simple. The TPP does not even need Congress's assent. The interesting thing to me is that much of the opposition to the TPP has come from the left, so they may actually agree with him on that one. I'm sure there are large segments of the electorate that are still opposed to NAFTA and would be happy to get rid of it. I don't see any good that could come out of these retrenchments, but if Trump's attacks on foreign trade are limited to these two items, I will consider us lucky.