Michael Gerson:

One outcome of and proof for ideological polarization is the way it has made stalwarts appear like centrists. In what world is Hillary Clinton - feminist heroine, author of Hillarycare, sworn enemy of the vast right-wing conspiracy - not progressive enough? In what parallel universe is Jeb Bush - a tax-slashing, school-voucher-supporting, pro-gun former Southern governor - some kind of moderate? George Wallace, who managed to be foolish on an amazing variety of topics, said that there wasn't "a dime's worth of difference" between the Democratic and Republican parties.

http://www.jewishworldreview.com/michael/gerson123014.php3