The Nassib border crossing, a crucial trade corridor on the Damascus-Amman highway, is set to reopen following three years’ closure. Syrian government forces retook the strategic point from Sunni rebel groups on 6 July as part of their campaign to recapture territory on the southern frontier.

Taken by the Free Syrian Army and Al-Nusra Front in April 2015, the closure effectively cut off Jordan, the West Bank and to a lesser extent the Gulf from overland trade from the north. In doing...