Cheered like a rockstar when he passed through Berlin five years ago on his way to the White House, Barack Obama faces a cooler reception and tough questions about U.S. spying methods when he returns next week for talks with Angela Merkel and a speech at the Brandenburg Gate.
The visit comes nearly 50 years to the day after President John F. Kennedy landed in a divided Berlin at the depth of the Cold War and, in a powerful message of American solidarity, told encircled westerners in the city: "Ich bin ein Berliner"
Kennedy is the U.S. leader Obama was most often compared with during his run for the presidency, when supporters chanted "Yes we can" at campaign rallies. Young, charismatic and inspirational, he represented hope, renewal and the clean break from George W. Bush that Europeans craved.
"Germany meets the superstar" was the headline on the cover of Der Spiegel weekly before his visit during the 2008 U.S. presidential campaign. His speech in Berlin's Tiergarten park attracted 200,000 fans who cheered wildly as he acknowledged policy mistakes under Bush and declared: "America has no better partner than Europe".
This week's Der Spiegel cover on the Obama visit was headlined "The Lost Friend".
Obama remains popular with Germans: a poll last week showed that 82 percent of them believe he has done a good job.
But the magic has gone, replaced by questions about Obama's failure to close the Guantanamo Bay military prison, his use of drones to kill al Qaeda militants and, above all, the "big brother" scanning of the Internet and communications that Europeans thought had ended with the Bush era.
Many Germans still recall blanket surveillance under the communist Stasi secret police, and when news of Washington's covert spying programme PRISM broke last week, the newspaper headline of choice was "Yes we scan".
"He is still popular but not like he was," said Henning Riecke, who heads the transatlantic relations programme at the German Council on Foreign Relations in Berlin.
"There's disappointment in Germany that he hasn't been able to close Guantanamo and there are concerns about his tactics in fighting terrorism. People have realised he's not a saint and he's not all-powerful."
Chancellor Merkel has owed Obama an appearance at the Brandenburg Gate, which once stood next to the Berlin Wall between the communist East and capitalist West of the city, ever since she rebuffed a request from the junior senator from Illinois to speak there in 2008.
This time he is due to address roughly 4,000 invited guests on the eastern side of the Gate, in the enclosed Pariser Platz square. U.S. officials were apparently reluctant to have him speak on the western side, next to the park, because they feared unfavourable comparisons with the turnout in 2008.
The hope in Merkel's camp has been that the visit can give her a boost in the run-up to an election in September when she will be fighting for a third term.
It will also give the two leaders an opportunity to trumpet a free trade initiative between the United States and European Union that both sides hope will boost economic growth, create jobs and give new meaning to a relationship that has lost its emotional grounding since the end of the Cold War.
For Obama, who grew up in Hawaii and spent part of his childhood in Indonesia, Europe has sometimes seemed an after-thought. The signature foreign policy initiative of his first term was his "pivot" to Asia.
German media have made much of the fact that it has taken 4-1/2 years for Obama to make his first presidential trip to Berlin.
"For Obama, the relationship with Europe has been close to a cost-benefit analysis. It's not in his gut," said Jackson Janes, head of the American Institute for Contemporary German Studies.
For her part, Merkel has been preoccupied for the past three years with Europe's financial turmoil. She has come under heavy pressure from the Obama administration to take bolder steps to resolve the crisis and to stimulate growth in Europe.
Merkel's aides, while describing the ties between the two leaders as good and respectful, also concede to strains.
At a G20 summit in Cannes in late 2011, they say Obama tried to persuade the French and Italian leaders at the time, Nicolas Sarkozy and Silvio Berlusconi, to gang up on Merkel and her euro policies. In 2012 at a G8 summit he hosted at Camp David, Obama embraced new French President Francois Hollande and his pro-growth message, leaving Merkel looking isolated and vulnerable as she pressed the case for austerity and reform.
When discussing Obama, advisers to the chancellor can sound nostalgic for Bush, who held regular videoconferences with Merkel, invited her to his ranch in Texas, and spent countless dinners quizzing her on her youth behind the Iron Curtain in East Germany.
SNOOPING AND SYRIA
Still, the similarities between Obama and Merkel are hard to ignore. Both are outsiders - the first black U.S. president and Germany's first woman leader, who grew up under communism.
Both are pragmatic, tactical leaders with a mastery of detail. When they met in Dresden on Obama's first visit to Germany as president, aides say a discussion on climate change turned into a competition over who knew more about carbon permits.
Talks in Berlin will also be watched for signs of tension. Merkel's spokesman has said she will press Obama for answers on the U.S. surveillance programme. Berlin wants assurances from Obama that the on-line exchanges of its own citizens are not being monitored from Washington.
Another major topic will be Syria, after the White House said the government in Damascus had crossed a "red line" by using nerve gas and that Obama had authorised sending U.S. weapons to rebels in the country for the first time.
On Friday, a spokesman for the German foreign ministry said the government had "learned of the American decision with respect" but was sticking with its position that it would not arm the rebels.
Merkel and Obama may try to shift the focus to their free trade initiative. An EU-commissioned study estimates the deal could generate economic benefits of roughly 100 billion euros per year on either side of the Atlantic.
"Despite the pivot to Asia it's the transatlantic marketplace that is galvanizing Washington's attention at the moment," said Charles Kupchan, a professor at Georgetown University. "American and European elites are desperate for growth and jobs and they don't have many arrows left in their quiver."