Look at the slogans Republican presidential candidates are running on: "Make America great again" (Donald Trump); "Believe again" (Louisiana Gov. Bobby Jindal); "Reigniting the promise of America" (Sen. Ted Cruz of Texas); "Restore the American Dream" (former Sen. Rick Santorum); "Heal. Inspire. Revive" (Ben Carson).

Notice a theme here? They're all about restoring and reviving something. That would be the Old America, when the country was whiter, men were in charge, government was smaller and religion more influential. And, Republicans would quickly add, the United States was more successful, more self-assured and a more powerful player on the world stage.

Democrats rally to the theme of diversity and inclusion. Sometimes they go overboard, like the San Francisco middle school teacher who refused to announce the results of a student council election because the winners were not diverse enough. Her critics howled, "Diversity trumps democracy!" — until she relented.