At the G20 summit beginning in the swish surroundings of Cannes, southern France on Thursday, Obama will test whether his own diminished political heft at home will weaken his economic leverage abroad as he girds for re-election. Obama has pressed behind the scenes for a strong European response to a regional debt crisis which threatens to spiral into global financial contagion, and despite some market doubts, welcomed a EU debt accord last week. Lael Brainard, Treasury Department undersecretary for International Affairs, said Obama still believed Europe had the capacity and resources to overcome its economic woes. "The challenges facing Europe have significant implications for the US economy and for the global economy," said Brainard. "The EU is a critical anchor of global stability and our single largest trading partner." While Obama has been encouraging European leaders from across the Atlantic in frequent telephone calls, his capacity to press for forthright action by his counterparts may be undermined by his diminished domestic political clout. The president has been unable to take the swift and sweeping action on the slowing US economy that he would like to, after Republicans in Congress refused to pass his $447 billion jobs package. The White House however rejects the idea that Obama's weight on the world stage has been hurt by his failure to forge further economic reform at home and argues his policies succeeded in staving off a second Great Depression. "He carries with him to France the fact that we are pushing our Congress to act on these matters, and he comes as the leader of the largest economy in the world and a great friend and ally of a great many nations," said White House spokesman Jay Carney. "We continue to have a significant leading role to play at the G20 and other international fora," Carney added. Obama will stress that international role soon after his trip to France, when he flies to his native Hawaii, to host the summit of the Asia Pacific Economic Cooperation forum (APEC) and attends an East Asia summit in Bali. Soon after arriving in France early Thursday, Obama will hold talks with French President Nicolas Sarkozy and German Chancellor Angela Merkel, his two top interlocutors on the eurozone crisis. While all sides stress their agreement, and Washington praises the deal reached at a European summit to stabilize the eurozone last week, there are clear hints of divergence on the global economy heading into the G20 meetings. Obama last week stressed the need for the "full development and rapid implementation" of the European plan amid fears that volatile continental politics could complicate its prospects. The president has several times worried publicly about the impact that European "headwinds" could have on the fragile US recovery, which is casting a cloud over his own hopes of winning a second term in 2012. White House officials also on Monday hinted at skepticism over a plan for a tax on financial market transactions pushed hard by Merkel and Sarkozy.