3. African-Americans. Paul’s support for the Civil Rights Act of 1964 has been equivocal. He thinks North Carolina’s new voting restrictions are no big thing. He co-authored a book with “the Southern Avenger,” Jack Hunter, a man who has written that Abraham Lincoln “had far more in common with the Nazi dictator than the Southern soldiers” and that the “congressional apology for slavery was completely illogical.” Paul put Hunter, an avowed secessionist, on his payroll in the U.S. Senate.

With his past statement and alliances, Paul could provoke an African-American turnout boom against himself in an election that otherwise might see less enthusiasm for the Democratic nominee than there was for America’s first black president. Paul has never had to seriously contend for the votes of a diverse electorate: Kentucky is less black (8.1 percent vs. 13.1 percent) and Hispanic (3.2 percent vs. 16.9 percent) than the U.S. average, according to the Census Bureau, and there is no question he is behind the curve when it comes to talking about race and justice in a diverse society in a way that does not raise the hackles of the very people he says he is trying to appeal to. And while even the most optimistic Republicans don’t expect to make very much headway with African-Americans in 2016, repeated controversies about race could be expected to resonate negatively among other groups of potential voters.