One guide to understanding the Trump Presidency, Tom Clancy's novel of a non-politician president, Executive Orders (1996).
What happens if we actually have a president who rejects the shibboleths of the Beltway in favor of median-voter positions on abortion, Taiwan, etc.?
And see how he copes with an Iran empowered by Iraq's destruction after the death of Saddam Hussein.
In the sequel, The Bear and the Dragon (2000), the non-Politician President, newly returned to office, has to deal with a China that resorts to war to cope with a rapid decline in exports.