The real issue behind the controversy that has erupted over plans to build a 15-story cultural center, mosque and madrassa a few yards from Ground Zero is not only about the mysterious funding behind the Cordoba Center initiative, or whether or not its founders and backers have malign intentions. It is primarily about understanding how Muslims across the world, in particular Islamists, would view the conversion of the site of the greatest Muslim attack on U.S. soil into a Muslim house of worship. Given the long history of mosque-building following Muslim military victories, the building of the Cordoba House on...