Donald Trump boosters often accuse his detractors of being "out of touch" with America. They point to his success in Republican primaries, and argue that it proves those who wrote off his chances of winning the nomination don't know what real America is about. Then they assume his success in Republican primaries will carry over to the general election. But this is a mistake, because general election voters are a lot different than Republican primary voters.

It's often been pointed out that general election voters are younger and more diverse than those who vote in Republican primaries, but I decided to quantify this – and the results are pretty revealing. I looked at GOP exit poll data in nine potential swing states and compared the percentage of white voters and young voters with the turnout among those same groups in the 2012 general election.

In the nine states I looked at, the white vote has averaged about 91 percent during the GOP primaries, but whites only made up an average of 77 percent of voters in those same states in the 2012 general.

Also, the 17 to 29 year old vote in those states has represented just under 12 percent of voters in the 2016 GOP primaries, but 18 to 29 year olds represented more than 17 percent of the 2012 voting pool that reelected President Obama. (Note: In a number of states, 17 year olds are allowed to vote in the primaries as long as they'll be 18 by election day. This does not account for the difference.)

A recent poll found Hillary Clinton crushing Trump among younger voters by 33 points. Trump, along with his passionate fan base, has perpetuated the idea that he'll win over black and Hispanic voters in a general election. But there is no empirical data to back this up.

In the 20 GOP primary states for which exit polls exist, not one of them had a high enough turnout among black voters to provide statisticians with a large enough sample size to break down how the vote split. Many Trump boosters have pointed to the fact that he won a plurality of Hispanics in the Nevada caucuses. But this tells us nothing. Trump's share of the Hispanic vote in Nevada represented just about 1 percent of Hispanics who voted in the 2012 general election.

The actual real America is one in which non-whites are a growing percentage of the electorate and in which younger voters have more of an influence in electing the next president.

Trump's racially-charged comments on Mexicans and Muslims and his hesitance to disavow the KKK have not been disqualifying for GOP primary voters. If anything, such controversies have merely burnished his anti-politically correct credentials among an electorate that does a collective eye roll whenever anybody suggests that racism is still a problem in this country.

But consider me skeptical that the younger and more diverse group of voters who will turn out for the general election will be as comfortable with Trump's casual appeals to white resentment as a plurality of the GOP electorate – sadly – is proving to be.