There are, it seems to me, at least four immediate reasons why Donald Trump has been a disaster for Israel and the Jews.

One: Donald Trump defers to Ann Coulter, with her long history of anti-Semitic rants, when he wants to know what the Republican grassroots are thinking. [...]

Two: An amoral, self-absorbed leader, Trump does what is good for himself rather than what serves the interests of America and its allies - Israel included.  [...]

Facing criminal investigations and crises of every sort, our President foments chaos to change the subject from yesterday's bad news and to make himself the story and the center of attention. And his disregard for expert advice is no oversight. One consults with advisors and allies when the intention is to bring order out of chaos; one acts alone when the intention is to do the opposite.

These are the responses of an impulsive, unbalanced man, patently unfit for his job. And for Israel, a powerful country but still a very vulnerable ally in a bad neighborhood, chaos and uncertainty have replaced the stability, security assurances, and military cooperation that the alliance with America has always delivered. 

As his resignation letter noted, James Mattis left his job as Secretary of Defense precisely because he saw how an unstable president was treating America's allies, and he realized that Trump's behavior was both profoundly wrong and dangerous for all concerned.

Three: The President remains a hostage to Vladimir Putin, for reasons still unknown, posing dangers to Israel that grow by the day.