On Sunday, a gunman stormed a gay nightclub in Orlando, Florida, killing 49 people and wounding 53 others. During the massacre and ensuing three-hour standoff with police, the shooter, Omar Mateen, called 911 and declared his allegiance to Islamic State. The group claimed responsibility the next day, proclaiming Mateen "one of the soldiers of the caliphate in America."
But U.S. officials cautioned that even if Mateen was inspired by Islamic State to undertake the worst mass shooting in modern U.S. history, there was still no evidence he had a direct link to the group — that he had been trained or instructed by its terror planners. Rather, Mateen might have heeded the call of Islamic State leaders to carry out "lone wolf" attacks in the West, especially during the holy month of Ramadan.
Two years ago, Islamic State militants marched into Mosul, Iraq's second-largest city. In quick succession, the jihadis captured a large swath of northern Iraq and consolidated their control over parts of Syria. Today, Islamic State has in many ways overshadowed al-Qaida as the world's most serious terrorist threat. Western and Middle Eastern security officials now view Islamic State as the greater danger to their domestic security, especially because of its mastery of social media and its ability to recruit thousands of disenchanted young Muslims into its ranks.