In military conflict, bridges figure large. Retreating armies want to blow them up to slow advancing armies; advancing armies want to capture and preserve bridges to aid forward progress. They even bring along their own.
The metaphor of bridges in warfare is one way to contemplate the homeland security problem of how to retard the advancing flow of illegal migrants from the Islamic world to America’s land borders. This human traffic — the sort that camouflaged at least three ISIS terrorists as they traversed to their attack on Paris — is primarily made possible by long-haul human smuggling networks, which bridge distant countries.
These smuggling networks provide the exceptionally long bridges that for years have made it possible for “special interest aliens,” or SIAs — the term for Syrians, Iraqis, Pakistanis, Somalis, Afghanis, Iraqis, Iranians, and the citizens of two dozen other countries where Islamic terrorism organizations exist — to reach the U.S. southwestern border. Given the vast distances to be covered and the necessary stolen passports, ill-gotten visas, fake identity documents, and corrupt airport customs officers who require bribes, ISIS terrorists would be hard-pressed to make the journey without the SIA smugglers.