Offering reassurance and resolve, President Barack Obama stood in the historic grandeur of Westminster Hall and served notice to England and the world that the growing influence of countries like China, India and Brazil in no way dictates a diminished global role for America and its European allies.
"The time for our leadership is now," Obama declared to members of Parliament, who for the first time gave an American president the honor of addressing them from the 900-year-old hall where great and gruesome moments in British history have played out.
"If we fail to meet that responsibility, who would take our place, and what kind of world would we pass on?" the president asked.
Tracing an arc from the allied soldiers who fought on the beaches of Normandy to the NATO-backed rebels now fighting in Benghazi, Libya, Obama argued that only the Western allies have the might and fortitude to promote and defend democracy around the globe.
Obama's message that U.S. and Europe remain vital on the world stage is one he is sure to carry with him as he heads next to Deauville, France, for a two-day summit of the world's top industrial nations. In addition to pressing economic matters, leaders will focus there, too, on how to support democracy in the Middle East and North Africa in a time of upheaval and economic strains.
In London, Obama urged patience in Libya and with the ongoing war in Afghanistan. He also renewed his determination to push for peace in the Middle East and voiced confidence that democratic stirrings ultimately would prevail there and in North Africa as Western allies stand fast.
Libyan leader Moammar Gadhafi and his regime "need to understand that there will not be a let-up in the pressure that we are applying," Obama said at a news conference with British Prime Minister David Cameron earlier in the day. "I think we will ultimately be successful."
Obama's vision of a relevant and revitalized U.S.-European partnership was a welcome message for Western allies who at times have displayed nervousness that the president has focused on the growing influence of Asia at their expense.
"It was wonderful to have the president here offering such a clear and unambiguous reaffirmation of our relationship," said British Education Secretary Michael Gove, a key ally of Cameron.
Opposition Labor Party legislator Rachel Reeves tweeted after the 35-minute speech: "Feeling uplifted and proud."
Addressing British lawmakers in an august setting, Obama leavened the formality of the occasion by speaking with warmth and humor, and his remarks went over well.
He spoke of the inspiration that "rabble-rousing" American colonists drew from their English forebears and invoked revered British leader Winston Churchill not once, but five times. Taking note that Westminster Hall's previous speakers had been the queen, the pope and Nelson Mandela, Obama joked that that trio represented "either a very high bar or the beginning of a very funny joke."
The president marveled that he stood before the lawmakers as "the grandson of a Kenyan who served as a cook in the British Army."
Mindful of the economic concerns that are predominant both in the United States and Europe, Obama argued that rather than fear Asia's rising influence, "we should welcome this development, for it has lifted hundreds of millions from poverty around the globe, and created new markets and opportunities for our own nations."
AP's Global Economy Tracker shows that the fastest-growing countries _ China, India, Indonesia _ are all in the developing world. The slowest are all European: Spain, Italy and Britain. The United States ranks 12th.
China, India and other major developing countries quickly returned to breakneck rates of growth after escaping the worst of the economic downturn in 2008 and 2009. Their rapid recoveries showed for the first time that emerging economies have grown big and strong enough to thrive independently while the United States and other rich countries struggle.
The president will now pivot to the Group of Eight meeting in France, where leaders will discuss ways they can financially support the fledgling democratic transitions in Tunisia and Egypt, and create incentives for other countries in the region to also seek greater freedom. Obama also will face questions about his military drawdown plans in Afghanistan and his renewed push for Middle East peace as well as the continued steps the world's leading economies are taking to recover from the global meltdown.
Westminster Hall, the setting for Obama's address to Parliament, was completed in 1097, and generations of rulers held coronation banquets there. It also saw the 1649 trial of Charles I, condemned to death as England briefly dispensed with its monarchy. The head of Oliver Cromwell, the military and political leader who led the ousting of the royal family, was later impaled on a spike and left on display outside the hall's entrance.
In a move rarely deployed in British politics, Obama worked the audience at Westminster Hall for almost 10 minutes after his speech, surprising lawmakers as he stopped for a series of brief chats. He spoke with Oscar-winning actress-turned-lawmaker Glenda Jackson, and won a peck on the cheek from Floella Benjamin, a much loved children's TV presenter and now member of the House of Lords.
Obama began his day in closed-door meetings with Cameron that were all about the practical realities of the U.S.-U.K. partnership in trouble spots such as Libya and Afghanistan.
The two leaders then took a break before their joint news conference to grill burgers for U.S. and British troops and spouses at a barbeque in the garden of Cameron's 10 Downing Street residence. The two briefly manned the grills, and then joined their wives, Michelle Obama and Samantha Cameron, in serving up plates of food.
Cameron joked in advance that his daughter was calling it the "Obama-cue."
And there was one more bit of ceremonial business to be taken care of before Obama heads off to France: The Obamas were hosting a reciprocal dinner for Queen Elizabeth II and Prince Philip at the U.S. ambassador's residence in return for the lavish state banquet that the royals threw for the Americans on Tuesday.
The guest list had a significant celebrity quotient, including actors Colin Firth and Tom Hanks, soccer star David Beckham, author J.K. Rowling and historian Doris Kearns Goodwin. The three-course menu included lobster ravioli, griddled filet of aged Highlands beef, crushed jersey royals with rosemary, asparagus and minted broad beans, topped off with classic pecan pie and brandy ice cream for dessert. Tony Award-winning singer and actress Kristin Chenoweth was providing the after-dinner entertainment.
Obama began his week with a feel-good visit to Ireland, where he visited the tiny village from which a great-great-great grandfather on his mother's side emigrated to the United States. He will end his four-nation tour of Europe in Poland, which he had hoped to visit last year before an ash cloud from an Icelandic volcano forced him to cancel.
Associated Press writers Julie Pace and David Stringer in London and Paul Wiseman in Washington contributed to this report.