A Republican U.S. Senate candidate's new cable television ad slams GOP-endorsed candidate Kurt Bills for his association with libertarian Republican Ron Paul.

The ad is the first aired in the U.S. Senate race that features Democratic U.S. Sen. Amy Klobuchar's quest for re-election. Neither Klobuchar, who leads in polls and fundraising, nor Bills have run any television ads yet.

Even the ad from Republican primary candidate David Carlson will not have a wide viewing. Carlson said he spent a few thousand dollars to run it in the western and southwestern suburbs. But it could make a mark on Bills, a Paul supporter who has struggled in his quest to unseat Klobuchar, in a low-turnout August primary. Bills said the ad was "kind of disturbing" and "disheartening."

"I am David Carlson and I approved this message because you have the right to know," he says in the ad as a photo of him with presumed Republican presidential nominee Mitt Romney appears on screen. A female narrator then takes over: "What would America have looked like if we had President Paul and Senator Bills?"

The ad hypothesizes that Paul's idea of "states' rights first" would mean there would be no civil war to free the slaves, women and minorities would have no right to vote, schools would not be integrated and African-American veterans could be forced to leave restaurants. It also lifts a former Paul staffer's claim that Paul said "saving the Jews was none of our business" in World War II. Those accusations about Paul have long rattled in political circles.

Bills, a freshman state representative, has not publicly supported any of the more extreme ideas pinned on Paul. Asked about it on Sunday, Bills said "this is Kurt Bills running and not Ron Paul" and emphasized that as a public school teacher he welcomes all students.

The ad, Bills said, "says more about the person who put it out than about me."

Rachel E. Stassen-Berger • Twitter: @rachelsb