He makes four points: the GOP has serious candidates, a harsh intra-party battle is unlikely, a "fringe" nominee is also unlikely, and an enthusiasm gap shouldn't be a problem. You should read his reasoning for reaching those four conclusions.
Points he doesn't make, but perhaps should have, include the following. Obama isn't generating, as President, the enthusiasm he did as a candidate. He is, however, generating lots of enthusiasm among those who want a different president.
Also to be considered, the President will have to try to make independents fear that four years under the Republican will be worse than the last four years under Team Obama. As former governors, the likely GOP nominees don't seem to lend themselves to that sort of demonizing.
