The common denominator in each of these mutations is an idea, based in fantasy and conspiracy, about Jewish power. The old-fashioned religious antisemite believed Jews had the power to kill Christ. The 19th-century antisemites who were the forerunners to the Nazis believed Jews had the power to start wars, manipulate kings and swindle native people of their patrimony.Present-day anti-Zionists attribute to Israel and its supporters in the United States vast powers that they do not possess, like the power to draw America into war. On the far right, antisemites think that Jews are engaged in an immense scheme to replace white, working-class America with immigrant labor. Tucker Carlson and others have taken this conspiracy theory mainstream, much to the delight of neo-Nazis like David Duke, even if they are careful to leave out the part about Jews.The man who attacked the synagogue entertained the same type of fantasy. Just as Willie Sutton was said to rob banks because “that’s where the money is,” this assailant took Jews hostage because that’s where the power was (or so he thought). The F.B.I.’s moral idiocy — there are no other words for it — in denying the specifically antisemitic nature of the attack lies in the idea that he could have imagined himself choosing just about any means to achieve his end, like taking hostages at the nearest church or convenience store. Similarly, the focus on his mental health evades the central fact that, crazy or not, his malice was not random. He aimed his gun at Jews.The fantasy about Jewish power may seem outlandish, but it’s far more pervasive than many think — which gets to the point of people participating in antisemitism even when they aren’t knowingly perpetrating it.Who, for instance, is most responsible for devising the war in Iraq? If your first-pass answer is “Wolfowitz, Feith, Abrams and Perle,” you might ask yourself why you are naming second- and third-tier Bush administration officials, all of them Jewish, when all the top decision makers — Bush, Cheney, Rumsfeld, Rice — are Christians. (If your response to this is that Wolfowitz et al. were the ones who pulled the strings, then you’re an antisemite.)Or take another example: if you think the reason Israel gets so much support in Congress is the money and influence of the pro-Israel lobby, you might be surprised to learn that that lobby ranks 20th on the most recent list of congressional donors, giving away a paltry $4.5 million compared with the $95 million that retiree interest groups donated. “All about the Benjamins” it is not, no matter what Representative Ilhan Omar might suppose.***But there’s a larger context here, which has to do with prevailing assumptions about power itself.