The US’s envoy to the UN visited southern Turkey on Wednesday to assess aid deliveries across the border into Syria as the Biden administration gears up for a likely showdown with Russia at the UN Security Council over the operation’s renewal. The council mandate for the long-running humanitarian operation, which Russia and China have already reduced to just one Turkish border point into rebel-held Idlib province in Syria at Bab Al-Hawa, is due to expire on 10 July. When the 15-member council first authorised cross-border aid deliveries into Syria in 2014, supplies were allowed to pass through…