Belgium Warned of Attacks. It Wasn't Enough.

Only days ago in Brussels, as Western leaders celebrated the arrest of a key terrorist suspect, Belgian officials warned that there were dozens more jihadists at large in the city and that more attacks were being planned. They couldn’t have known how right they were.

I traveled to Brussels on March 16, to attend the German Marshall Fund's Brussels Forum, a meeting of U.S. and European officials, foreign policy experts and journalists, where the fight against terrorism was at the top of the agenda. Two U.S. senators and several Obama administration officials who attended had just passed through the main terminal of the Brussels airport. On Tuesday morning, it was hit by what Belgian authorities described as a suicide attack. At least 26 were killed and many more wounded at the airport, and in a parallel attack on the city's subway system.