You have a lot of good points here and I hope people aren't glossing over because of the length.
Also, you do a great job of talking to the difference between campaign promises, actual positions, implied threats, and action. Of course, the easiest way to prevent war is to install a president who LOVES war and plays with G.J. Joe figurines all day -- other countries would be scared shitless, the Middle East would STFU and the pivot to Asia would actually work; and the legislature and public wouldn't support them anyway even if they did have a good cause for war. To guarantee a war, put in a puppet who doesn't care about war, but then put someone who stands to profit greatly from war right next to their ear.