WASHINGTON/GENEVA/DUBAI: Even for a US president long fixated on deal-making, Donald Trump’s assignment of his favorite envoys to juggle two sets of negotiations – the Iranian nuclear standoff and Russia’s war in Ukraine — in a single day in Geneva has left many in the foreign policy world scratching their heads. The shuttle diplomacy on Tuesday by US special envoy Steve Witkoff and Trump’s son-in-law Jared Kushner has raised questions not only about whether they are overstretched and outmatched, but about their serious prospects for resolving either of the twin crises, experts say.