“These are people I’ve gotten to know over the years,” Trump began. “It started around 2015, and then went into 2016 when the presidency began—officially began—but I’ve known him actually, for a long time.”
Archive article: https://archive.ph/FbA9d#selection-1403.0-1403.206
Well, there’s a few pretty obvious reasons. The main one being the consequences. Additionally, one would require the means and opportunity to do it and the time to plan it. Also consider that America is a huge place and the president doesn’t bother to visit every part of it. Someone who was inclined to do that may have to travel hundreds or thousands of miles to try. Lastly, the idea of taking a human life is abhorrent to most people.