In an interview that aired Sunday, Paul said that those immigrants "are not bad people" but added the United States "can't invite the whole world" inside its borders.
Paul, the Kentucky Republican eyeing a 2016 campaign, says Bush should have kept his focus on controlling the U.S. borders.
Bush, a former Florida governor, says the GOP cannot demonize immigrants and should show compassion. He described illegal immigration as an "act of love" by people trying to provide for their families.
Paul was interviewed on ABC's "This Week" during a visit to early nominating New Hampshire.
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