The fact that a document of such limited scope took more than a month of haggling underlines the difficulties ahead as the two neighbours move on to substantive negotiations. The impasse was broken only after American intervention, including a visit by David Walch, US charg d'affaires in Saudi Arabia, to President Salih in Sana'a.
American involvement is one of the few grounds for optimism in an otherwise bleak picture.
Recognising that the confrontation could threaten its own strategic interests, the US appears to be quietly shepherding the two neighbours towards a settlement. The 11-point document reflects concessions by both sides. Yemen appears to have conceded the possibility of settling the border in more than one stage. The Saudis have given ground on the question of military supervision and have accepted the principle of arbitration if no mutual agreement on the border is reached. But since most of these things have been a routine feature of Saudi-Yemeni relations for years, there will be ample scope for either side to accuse the other of infringing the accord and to use it as grounds for pulling out of the deal if they feel so inclined.