If every word written and uttered since the US presidential election about the dire need for bipartisanship in American politics was worth a dollar, the total would go some way towards avoiding the so-called fiscal cliff and the threat of another economic crisis that is now spooking financial markets. But since they are not, we will have to hope for a bipartisan spirit in negotiations to break the deadlock between the White House and Congress if the US economy is not to tip into a recession that will have consequences for the rest of the world. The call for unity might seem directed at the socially and fiscally conservative Republicans among the majority in the House of Representatives. There are understandable concerns that despite the failure of an election strategy focused on white male voters, they may not accept the legitimacy of a victory forged in contemporary constituencies from African-Americans to Hispanics and to single educated women, who helped re-elect Barack Obama. Political strategists are supposed to be realists. But an enduring image of the Republican debacle was the reluctance of Karl Rove, mastermind of George W. Bush's two victorious campaigns, to accept the result in the key swing state of Ohio, where he demanded a recount even as Mitt Romney conceded defeat. The president may have led the call for unity but he, too, must heed it. He is known for his oratory and message of hope and change. It is time to deliver and secure his legacy. But first he must break the political deadlock in Washington. He needs to wind back the oratory, come down from his perch in the White House and deploy the power and authority of his office on the ground. That means engaging more in the political process - negotiating, bargaining, persuading and, where necessary, arm-twisting. That is the way his more effective predecessors got things done. Presidential aloofness and congressional intransigence fail the challenges of fiscal solvency, growing inequality and climate change. Americans must come together if their system is to work properly.