A new beginning of diplomatic engagement – that is the message President Barack Obama has made to Iran in an unprecedented videotaped recording.In a major shift from former President George W. Bush’s isolationist policy, Obama expressed an openness to direct diplomatic contact. “We have serious differences which have grown over time,” said the US president. “My administration is now committed to diplomacy that addresses the full range of issues before us, and to pursuing constructive ties. This process will not be advanced by threats. We seek instead engagement that is honest and grounded in mutual respect.” Timed to coincide with an Iranian holiday, the tape has been released to select Middle East broadcast outlets. For several decades, Tehran’s leaders have been locked in bitter disputes with Washington over support for militant Islamic groups and more recently the country’s nuclear ambitions.