His 26-hour whirlwind visit to the German capital caps three days of international summitry for the president and marks his return to a place where he once summoned a throng of 200,000 to share his ambitious vision for American leadership.
That was 2008, when Obama was running for president and those who supported him at home and abroad saw the young mixed-race American as a unifying and transformational figure who signified hope and change.
Five years later, Obama comes to deliver a highly anticipated speech to a country that's a bit more sober about his aspirations and the extent of his successes, yet still eager to receive his attention at a time that many here feel that Europe, and Germany in particular, are no longer U.S. priorities. A Pew Research Center poll of Germans found that while their views of the U.S. have slipped since Obama's first year in office, he has managed to retain his popularity, with 88 per cent of those surveyed approving of his foreign policies.
Obama also has an arc of history to fulfil.
Fifty years ago next week, President John F. Kennedy addressed a crowd of 450,000 in that then-divided city to denounce the Soviet bloc and famously declare "Ich bin ein Berliner," German for "I am a Berliner." Since then, presidents from Ronald Reagan to Bill Clinton have used Berlin speeches to articulate broad themes about freedom and international alliances.
Obama, fresh from a two-day summit of the Group of Eight industrial economies, will speak at the Brandenburg Gate, a symbol of Germany's division and later reunification. It is a venue that German Chancellor Angela Merkel denied him in 2008, saying only sitting presidents were granted such an honour.
The past context — and the weight of it — are not lost on the White House.
"This is a place where U.S. presidents have gone to talk about the role of the free world essentially," said Obama's deputy national security adviser, Ben Rhodes. "He is seeking to summon the energy and legacy of what's been done in the past and apply it to the issues that we face today."
Rhodes said Obama will make the case that even though the Berlin Wall came down 23 years ago and the threat of nuclear war has dissipated, the type of activism apparent during the Cold War needs to be applied to such current challenges as climate change, counterterrorism and the push for democratic values beyond the United States and Europe.
A senior administration official said Obama will also renew his call to reduce the world's nuclear stockpiles, including a proposed one-third reduction in U.S. and Russian arsenals. He is not expected to outline a timeline for this renewed push. The official insisted on anonymity in order to preview the issue before the president's speech.
Obama will also hold a joint news conference with Merkel.
The visit was attracting widespread attention in Germany. People waved and snapped photos as Obama sped by after his arrival and a thick cluster awaited the motorcade as it passed the Brandenburg Gate. An evening news show in Berlin devoted itself to the president's visit, highlighting "Das Biest," or "The Beast," as the president's armoured limousine is called.
There have been a few small protests, including one directed against the National Security Agency's surveillance of foreign communications, where about 50 people waved placards taunting, "Yes, we scan."
Merkel has said she was surprised at the scope of the spying that was revealed and said the U.S. must clarify what information is monitored. But she also said U.S. intelligence was key to foiling a large-scale terror plot and acknowledged her country is "dependent" on co-operating with American spy services.
For Merkel, the visit presents an opportunity to bolster her domestic standing ahead of a general election in September.
The U.S. and the Germans have clashed on economic issues, with Obama pressing for Europe to prime the economy with government stimulus measures, while Merkel has insisted on pressing debt-ridden countries to stabilize their fiscal situations first.
But the two sides have found common ground on a trans-Atlantic trade pact between the European Union and the U.S. At the just-completed G-8 summit, the leaders agreed to hold the first talks next month in the U.S.
Associated Press writers Julie Pace, Robert Reid and Frank Jordans in Berlin contributed to this report.