Political parties, not voters, choose their presidential nominees, a Republican convention rules member told CNBC, a day after GOP front-runner Donald Trump rolled up more big primary victories. "The media has created the perception that the voters choose the nomination. That's the conflict here," Curly Haugland, an unbound GOP delegate from North Dakota, told CNBC's "Squawk Box" on Wednesday. He even questioned why primaries and caucuses are held.