From NBC's Lindsey Pritzlaff and Lauren Appelbaum
While McCain was elaborating on the "stark differences" between his Democratic opponents' positions and his own, he slipped up.
"I'm a proud conservative liberal republic -- conservative Republican," he said.
After joining with the Richardson, Texas, crowd in hearty laughter, McCain went on to say what he initially meant.
"Hello, easy there," he said. "Let me say this. I am a proud conservative Republican and both of my possible or likely opponents are liberal Democrats."