Okay, but how is that any different from any other election? This is a description of American politics, not a reason why Trump will win. And considering there are more people who describe themselves as Democrats than Republicans, if this were
so impactful then it would in fact hurt Trump.
Every President has a large loyal core of supporters. Nixon had an approval rating in the twenties, and he was being successfully impeached (with help from his own party).
This just seems untrue. I think it's rather the opposite. The grass is always greener on the other side, and people get tired of the same old. It's also easier to make empty promises when you haven't had to break your previous empty promises the last four years. Government fatigue is a very real thing.
How is this an argument?
Israel usually supports the Republican candidate, and most American Jews still usually vote for the Democrat.
Hillary Clinton got 3 million more votes than Trump, and she was an historically unpopular candidate.
It mostly brings people who were already going to vote for Trump. For that matter,
as this graph shows, there are about as many people who favour increased immigration as favour decreased immigration.
The US army usually support the Republican.
About as many Biden-supporters voted for Hillary, as Hillary-supporters voted for Obama.