He could be a guitar player.
I noticed that his left hand fingernails are shorter than his right. That's a pretty strong clue that he is a fingerpicker. Mine are trimmed similarly. But I'll be the first to admit that it doesn't look presidential.
My guess is that it's as studied and contrived as everything else about this doofus. He wants everyone to notice his right-hand nails are longer. Oh, he must be a really, really good guitarist! He is so talented - guitar, windsurfing, killing gooks - he does it all!!