Jews controlled everything, so they would make it happen. jews controlled the government, jews controlled the banks, jews controlled the media. he truly believed this. >> it's a prejudice that's rooted in a conspiracy theory. >> reporter: debra lipstadt is widely considered one of the world's foremost experts on anti-semitism. >> anti-semitism has the strange title of the oldest or the longest hatred. hating jews is very convenient. >> why? >> you need someone to blame if there's a plague in your town. you need someone to blame if the economy goes bad. you need someone to blame if the war is l...