WASHINGTON  When President Bush welcomed leaders from around the world to the White House on Friday night, for what may well be one of the last formal dinners of his administration, the topic was the fragile world economy and the lush menu, belying the financial crisis, featured thyme-roasted rack of lamb. But the real story was in the seating chart.

There, in the State Dining Room beneath a massive portrait of Abraham Lincoln, to Mr. Bush’s right was President Luiz Inácio Lula da Silva of Brazil, who has complained loudly that developing nations like his were being “infected with problems” not of their making. To Mr. Bush’s left sat a leader with a fat checkbook and the power that comes with it, President Hu Jintao of China.

It was a startling illustration of the way the financial crisis, which originated on Wall Street and has spread around the globe, has remade the international economic world order. By insisting that developing nations be included in the summit meeting, President Bush gave fresh clout to their leaders, each of whom arrived in Washington with his or her own agenda.

But it will be up to a new United States president, Barack Obama, to figure out how to juggle those competing interests  and quickly. The declaration adopted by the leaders on Saturday calls for a second summit just 101 days after Mr. Obama is sworn in. All around Washington this weekend, as black motorcades sped about town and fancy hotels were marked off with the tell-tale police barricades, a sure sign a world leader was in residence, was evidence of Mr. Obama’s challenge.