Lest the world forget, a war is still raging in Gaza. Among the many obstacles to even a modest cease-fire, there is the Philadelphi corridor. Less than nine miles long and roughly as wide as a football field, it occupies a crucial border location — including the Rafah crossing — between Egypt and Gaza. Egypt patrolled its side of the border after the 1979 peace agreement, then the Palestinian Authority took over control when Israel withdrew from Gaza in 2005. But the PA was itself driven out by Hamas in 2007. Since then, the Rafah crossing has been a central...