Despite Barack Obama's reminder that "there is only one president at a time," with the increasing urgency of the economic issues facing the country, America's President-elect is taking a more active role. This weekend he called for a stimulus plan to create two and a half million jobs. Just two hours after President Bush's news conference on the economy this morning, Obama held another one. Bush defended the government's weekend decision to bail out Citigroup; Obama announced his new economic team. While the two have pledged close co-operation, how difficult is it to address a crisis with one president leaving office and another one in the wings?