The Guardian view on Iran and Saudi Arabia: a cautious start | Editorial

Plans for the two countries to restore diplomatic relations are welcome, but are only a modest step forward

Perhaps the first major diplomatic example of a post-America Middle East," wrote one analyst. He was describing Iran and Saudi Arabia's agreement last week to resume diplomatic relations - a surprise to most observers, and something of a coup for China, which brokered it. The volatile rivalry between the two nations has been one of the great geopolitical faultlines since the Iranian revolution of 1979. Security concerns, claims to regional leadership, ethno-sectarian rivalries and other factors have all played their part. The repercussions have been profound. The tensions contributed to Iran's all-out support for the Syrian regime, fuelled the war in Yemen, where more than 150,000 have died, and accelerated the disintegration of the state in Lebanon. Ties were cut in 2016 when Iranian protesters stormed Saudi diplomatic missions over Riyadh's execution of a revered Shia cleric.

But while last week's announcement was welcome, it is only a beginning. Assuming the deal goes ahead - there are two months for details to be ironed out - the containment of Saudi-Iranian tensions will not necessarily lead to a deeper rapprochement, let alone end Lebanon's woes or the complex and multifaceted conflict in Yemen.