The writer is Kissinger Chair at the Library of Congress and senior fellow at the Brookings Institution

An international conference hosted by Germany on Sunday secured a promise from several outside powers to stop interfering in the armed conflict in Libya. It also provided a sobering glimpse of the future of conflict diplomacy in the 21st century.

The two main actors vying for control of the country — the head of the UN-backed government, Fayez al-Sarraj, and the rebel general Khalifa Haftar— were present but not at the table. (Still, they agreed to staff ceasefire talks.) The key signatories were Algeria, Egypt, Turkey, the United Arab Emirates and Russia, whose supplies of arms and mercenaries have fanned the conflict into a conflagration. China, another co-signer, has long-term oil industry and infrastructure investments to protect.