"All the candidates will see which one can out-liberal the other," Rubio said.
Businessman Donald Trump on Tuesday targeted Republican presidential rival Marco Rubio, suggesting the Florida senator is a "perfect little puppet" to donors.
Jesse Byrnes 10/13/15 08:34 AM EDT
Paul said caucus members reflect "the greater will of the party."
The fourth GOP debate will be held in Milwaukee, Fox Business Network announced.
Clinton was joined by union members who are lobbying to organize at the hotel.
Trump trails in matchups with top Democratic candidates, however.
Trump said he expects "a very boring two hours."
It appears the vice president will not be making a surprise appearance in Las Vegas.
He said he will lay out proposed reforms to Social Security later in the campaign.
Bernie Sanders is about to stand before the biggest TV audience of his life.