I wouldn't say that there's much anti-semitism "on both sides of the spectrum" so much as a tremendous amount of it on the left. You'd have a hard time meeting an anti-semite at a Tea Party, for example (unless it's one of the crashers), and I haven't heard a prominent Republican say anything even remotely anti-semitic in decades (compared with Democrats, especially in the Congressional Black Caucus, who say some fairly outrageous things about Jews). In fact, one of the things that's gotten Pat Buchanan marginalized in conservative circles is his take on Jews and Israel. OTOH, it's become rampant on the left. Every antiwar rally since Desert Storm has featured a serious anti-semitic current. For example:
And those were in San Francisco, not Paris, London or Gaza. Unfortunately, anti-semitism is on the rise globally, and you can thank the left for it.