Plurality Rule and the US Presidency

The first, short appendix to my book on mixed electoral systems shows how the US Constitution confuses majority with plurality rule, and thereby fails to ensure an orderly transition of power in an entirely feasible sort of situation.
Here's that two page appendix excerpted (i.e., the book opened to p. 183):

Is any of this a real problem? I think so. Americans seem to me to be characteristically bewitched by the idea that their Constitution is like a self-contained, logical machine/precision clock (designed by geniuses, possibly with God's help), and that this leads them to regard collegiality, background conventions and understandings, etc. as fungible, and as fair-game to being lawyered away in the name of partisan success. (Other jurisdictions' citizens seem to me to be less enamored with their respective constitutional instruments, and commensurately more aware of their constitutions' ultimate dependence on lots of must-not-be-lawyered-away background good will and shared conventional understandings.) Americans therefore seem to me to be uniquely likely to eventually drive their in-fact-not-at-all-precise Constitution off the rails wherever that's logical permitted. Look out.