TEL AVIV — King Abdullah II of Jordan and Prime Minister Benjamin Netanyahu of Israel have not exchanged a word for 20 months, despite the 30-year-old peace treaty between their countries and lengthy shared border, but they found themselves on the same side of the divide on Sunday. 

A Jordanian truck driver carrying goods from Jordan to the Israeli-occupied West Bank pulled out a gun at the border crossing’s cargo terminal and killed three Israeli civilian guards. He was shot dead by other guards.

The border crossing — known by Israelis as the Allenby Bridge and by Jordanians as the King Hussein Bridge — mostly serves the millions of Palestinians living in Jordan and the occupied West Bank. Despite ongoing Israeli-Jordanian political tensions over the years, the crossing has been relatively calm. Since Sunday, Israeli and Jordanian officials have been working in close cooperation to determine whether the driver — Maher al-Jazi — was a lone wolf or was part of a network.

Clearly, the possible emergence of a new front between Israel and Jordan is the last thing either leader needs. Since the Hamas massacre 11 months ago and the ensuing Israeli war on the Gaza Strip, Netanyahu has been juggling fronts from Gaza to Lebanon, the Golan Heights and the Red Sea. King Abdullah battles persistent risks of domestic instability, constantly exacerbated by opposition to Jordan’s peace treaty with Israel and tensions over the Jerusalem sites sacred to Islam and Judaism, which could turn into a real crisis if a rare wave of anti-Israeli attacks suddenly emerges from Palestinian refugee camps throughout the kingdom.