Jeff Jacoby reminds us that the virulent anti-Semitism that President Ahmadinejad expressed last week is commonplace in the Middle East. And such hatred of the Jews often accompanies the actual attempt to exterminate Jews.

That coin -- virulent anti-Semitism -- circulates throughout the Muslim Middle East, not just in Iran. Ahmadinejad's ugly outpourings were condemned in the West, but they provoked almost no protest in Arab and Muslim countries, where Jews are routinely portrayed as evil subhumans fit only for extermination. In much of the Islamic world, Jew-hatred saturates the airwaves, spills from the mosques, fills the classrooms, permeates the press. Jews are represented as pigs and monkeys, as liars and connivers, as vile, hook-nosed scum who deliberately infect children with AIDS and poison Palestinian water. In their quest for power and world domination, they are said to be ruthless and devious. They were behind the 9/11 attacks, for example, and tipped off 4,000 Jews to stay home from the World Trade Center. And, of course, they concocted the "hoax" of the Holocaust, as part of an elaborate plot to establish a beachhead in the Middle East and extort money from the world.

Outsiders are rarely aware of how intense the Muslim world's Jew-hatred is. "What has surprised me is the virulence of this new anti-Semitism throughout all the Muslim countries," the distinguished journalist and editor Harold Evans wrote in 2002. "It is frenzied, vociferous, paranoid, vicious, and prolific, and is only incidentally connected to the Palestinian conflict." It is not the Israeli-Palestinian conflict that accounts for this loathing of Jews. It is the loathing of Jews that accounts for the Israeli-Palestinian conflict.

Obsessive anti-Semitism almost always characterizes the most dangerous threats to America and the West. Nazism, Communism, Islamofascism -- one thing they have in common is intense anti-Semitism. Which is why Ahmadinejad's strident rhetoric should be setting off urgent alarms. Dictators who talk about wiping nations from the face of the earth generally mean what they say. We should know by now that it isn't only Jews who are endangered by the mullahs and their threats. All of us are. And time is wasting.