"They've struggled to elect and actually have not been able to successfully elect their moderate candidates, the mainstream candidates," Schultz said on CBS's "Face the Nation".
"The Tea Party candidates seem to be winning because the Tea Party Republicans are energized in their primaries. So it has really caused, I think, a pretty difficult problem for them going into the November elections because they have candidates like (Joe) Miller who are on the extreme right-wing fringe who want to end Medicare as we know it, yank the rug -- the safety net out from under our senior citizens," she said.
Miller has gone head to head in a Republican primary with the incumbent Republican senator from Alaska Lisa Murkowski.
Miller, who also appeared on the show, said, "I simply want to get back to basics, restore the constitutional foundation of our country."
"And that means the federal government becoming less onerous, less involved in basically every item of our lives," he said.