The former US vice-president, Joe Biden, a Catholic, crossed himself – and a bipartisan audience of city mayors laughed and applauded. Democrat Biden, 76, did not declare he was running for president on Thursday but, to many in the room, it looked that way. His speech at the US Conference of Mayors in Washington DC was a plea for national unity and healing, an urgent warning about climate change and a counterintuitive pitch that Democrats’ best hope for the future lies in the past. 'But where I come from, I don’t know how you get anything done until we start talking to one another again.'

Joe Biden pleads for unity in hint at what his 2020 run may look like