"One 4-year presidency does not have to mold the history or legacy of a country." What actually happens after 4 years though? Isn't the concern, the supreme court ruling that the president is above the law? So laws like, you can't run for more than 2 terms, you must have a democratic election where everyone gets a vote, basically all laws around elections, no longer need be followed. Or for that matter any other laws. A president could seemingly behave like Hitler and face no justice. Trump won't live forever, but what's to stop him handing over to someone similar? (BTW to your main point, I agree indeed Europe has its major issues too)