Nearly 30,000 foreign recruits have now poured into Syria , many to join the Islamic State, a doubling of volunteers in just the past 12 months and stark evidence that an international effort to tighten borders, share intelligence and enforce antiterrorism laws is not diminishing the ranks of new militant fighters.
That grim appraisal coincides with the scheduled release on Tuesday of a six-month, bipartisan congressional investigation into terrorist and foreign fighter travel, which concludes that "despite concerted efforts to stem the flow, we have largely failed to stop Americans from traveling overseas to join jihadists."
The focus on shortcomings in the global effort to combat the Islamic State, also known as ISIL or ISIS , is playing out as tens of thousands of refugees flee strife in the Middle East and North Africa, including many seeking to escape the violence in Syria and oppression in areas under the control of the Islamic State.