Professor Bill Schneider (REUTERS) Commentary: Yes, the nation is polarized. So why aren’t the most extreme candidates winning?

“I have a mandate from the people, “ Donald Trump insists. The GOP front-runner is using that argument to resist pressure from Republicans to moderate his abrasive style and become more “presidential.”Trump does , of course, have some claim to a mandate to lead the Republican Party. He defeated 16 other Republican contenders. As of May 15, Trump had won about 11 million Republican primary votes out of 27 million cast. That’s 41 percent — not quite a majority.Trump will face an entirely different electorate in November, though. About 129 million Americans voted in the 2012 presidential election. Republican nominee Mitt Romney won nearly 61 million — and still lost. In order to win the White House, Trump will likely have to gain at least 54 million new supporters.Trump knows that he won the Republican nomination by being caustic and provocative. Not a typical politician. Why should he change? “You win the pennant and now you’re in the World Series,” Trump told the New York Times. “People like the way I’m doing.”Trump appears to be defying the Nixon rule. “Run to the right in primaries,” President Richard M. Nixon once advised Republican candidates, “and then to the center in the general election.” Does that rule no longer apply?Click here for the full article.