I really try to avoid political discussions on HN, as I dislike both of the major parties. I would suggest you read a book called 'Operation Troy', what Obama did IMO is much worse than revoking a visa, he extrajudicially killed an american citizen with a drone strike not in the field of battle.

You avoid political discussions by bringing up a completely unrelated subject that attributes negatively to an ex president?

So if I read a book about Obama abusing the power of the US presidency, how will that impact my thinking about whether the approach to border policy has changed under the new administration?