The Most Powerful Man in America ...

... is Supreme Court Justice Anthony Kennedy who was on the winning side of all 24 5-4 SCOTUS decisions this term, thus making him the pivotal swing vote. Moreover, he was on the losing side of only 2 of the 71 cases in which he voted. See Volokh. Granted, he doesn't have his finger on the nuclear button, but even the President lacks Kennedy's de facto to singlehandedly establish law. In our lexcentirc society, that's an enormous amount of power for one person to possess. Indeed, query whether the Founders ever intended for one man to wield this much power.