These observations were suggested by a presentation by retired US diplomat Efraim Cohen at Netanya AACI. They are my views, and do not necessarily represent his positions on the issues.
First of all no President can reverse many years of a specific program or treaty overnight. Such changes usually take years, because often Congress is involved and it takes time to build a consensus and pass legislation. Second, the reversal of long-term financial treaties, such as NAFTA, that involves several countries, cannot be simply reversed. The other signatories have to be consulted and negotiated with (as in Brexit). Also, such items as building a several hundred mile wall takes years of planning and costs millions of dollars. Where is the money gong to come from, not Mexico.
We must accept that statements and promises made by Trump during the campaign will not necessarily be followed when he is in office. At the time they got him votes, now to govern he must be more circumspect and rational. Such a policy as the “wall” may simply turn out to be an improving of the ability of the US to prevent illegal immigration. Already the promise to deport 8 million illegals has been whittled down to 3 million criminal illegals. Since many of them are already in jail that represents the easiest way for Trump to satisfy that aspect of his policy. With regard to his financial promises, he can simplify the tax code and reduce the tax payments, but that will take years, and in fact the loss of Government tax income could be catastrophic for Government expenditures, including an expansion of the military. In that respect Trump’s policies are contradictory, he wants to stop waging unnecessary wars, but expand the military.
With regard to Israel, maybe some are too enthusiastic, such as Naftali Bennett, Head of the Beit Yehudi party, who immediately went public with his expectations. Building of US embassies can take at least 2 years and more likely four, given the security considerations. However, in the case of Jerusalem there are complications. The US Consulate in Jerusalem does not answer to the US Embassy in Tel Aviv, because the US does not recognize Israeli sovereignty over Jerusalem. In fact the Consulate is independent and is assigned to the PA in Ramallah, not even to Jerusalem (it is not situated in Ramallah for security reasons – too dangerous). One way that Trump could finesse the situation is to transfer the Consulate administratively under the Ambassador in Tel Aviv. But, any such change will be resisted mightily by the State Department and all of those who want to see a “two-state solution,” and who are pro-Palestinian.
Trump said he wanted to “drain the swamp” of Washington DC, in doing so he might include the pro-Arab faction in the State Dept. But that is almost impossible since there are so many Arab countries with US Ambassadors that they form a clique that cannot simply be removed. But, in this day and age of modern electronic communication it is much easier to out-flank them and go directly to the leaders of those countries.
Since Trump is such an unknown quantity with regard to his policies and he has already apparently dropped several strong promises, at this stage even an educated guess would be no more than a guess.