Well, not to paint with a broad brush, but I don't recall any Republican (other than Buchanan, who, as you said, has left the GOP because he's not welcome) running for or serving as president or running for or serving in either house of Congress making an antisemitic remark or gesture publicly in my lifetime. Contrast that with Jesse Jackson, Al Sharpton, James Moran, Hillary Rodham Clinton, Ernest Hollings, the afformentioned John Dingell, Charlie Rangel, Cynthia McKinney, Ron Dellums, Gus Savage, and a list almost too long to spell out.
Publicly, James Baker. Bush One should have dealt with that, he didn't. Even marginally, other than Duke, reviled by Republicans, and the House candidate from Tn in 04, also reviled, I don't think there are any in the last 20 years or so. The Republican Party does a far better job of reviling these bigots than the Dems, who look at them as votes. But no, they get no credit.