After briefly appearing to falter, US-Iran implementation talks are back on track, with senior American and Iranian delegations converging on Switzerland for what could prove a decisive phase in turning a fragile wartime memorandum into a broader political settlement.

An end to fighting and relief from a global energy crunch is a welcome development, but critics say the US may have rushed into a bad deal. US-Iran talks in Switzerland will…

A White House spokesperson said that the "logistics of these negotiations have never been simple or predictable."