WASHINGTON, April 19 -- Global finance leaders, whipsawed by Middle East war news, came to grips this past week with their inability to mitigate the economic damage from increasingly frequent geopolitical shocks, and a realisation that counting on US leadership to resolve crises is no longer the guarantee it had long been.

At International Monetary Fund and World Bank Spring Meetings in Washington, participants swung from gloom over a worsening global economic outlook due to deepening energy price and supply shocks to tentative optimism as it appeared Iran may reopen the Strait of Hormuz and allow flows of oil, gas, fertiliser and other commodities to resume.

By yesterday that optimism was already fading amid new attacks on shipping. Th...