Back before campaign promises needed to be cashed, Barack Obama told 200,000 Berliners that allies must "trust each other" and vowed to repair bonds torn by George W. Bush's go-it-alone diplomacy.
Six years on, he needs to do some work to make good on that pledge.
Sectarian chaos remaking the Middle East, Edward Snowden's bombshells on US spying in Europe and political choices made in turbulent times, have again put US alliances under pressure.
A European swoon spurred by Obama's Berlin speech as a presidential candidate in 2008 peaked with a premature Nobel peace prize a year later.
But when he looked to Asia rather than requiting Europe's crush, the relationship began to cool.
It took Snowden's revelations to provoke a crisis in Germany where allegations of US Internet and phone surveillance recalled Big Brother East German communists.
Germans were furious US spies tapped Chancellor Angela Merkel's phone, and sent the CIA station chief home over a double agent scandal last week. German Finance Minister Wolfgang Schaeuble said US conduct "makes you want to cry."
It's all a long way from 2008.
"Europe had such extraordinary expectations of President Obama and what he could do. We have seen in the last several years, a managing down of those expectations," said Heather Conley, an analyst at the Center for Strategic and International Studies.
Though contrition has been lacking from Washington, it may not take too much to make amends: though Obama's popularity has ebbed – he retained the confidence of 71 percent of Germans in a Pew Research poll, a rating that he would relish at home.
Relations with France are better.
Paris and Washington combined to overthrow Moamer Kadhafi in Libya and forged anti-terror alliances in Africa, while beleaguered President Francois Hollande basked in a White House state visit earlier this year.
Since then however, spats over a $9 billion US fine for French bank BNP Paribas and French plans to sell warships to Russia have tempered US-French amity.
There is always the "special relationship."
But Britain has turned from the world stage, preoccupied by its own schizophrenic relations with the EU and Scotland's flirt with independence.
Britain's constancy as an ally was also questioned when Prime Minister David Cameron couldn't get parliament to back strikes on Syria over chemical weapons, foreshadowing Obama's defeat by a war weary Congress.
Washington has its own beefs with Europe, as it tires of the EU's reluctance to toughen sanctions on Russia over Ukraine. The Pentagon meanwhile frets at eroding European defense spending.
Still, Obama hails NATO as "the strongest alliance in the world" and traveled to Poland last month to bolster defense guarantees to former Soviet bloc allies.
Middle East maelstrom
Washington's Middle Eastern alliances are scrambled by sectarian unrest, civil wars, coups and revolutions.
The administration has struggled to keep pace with power shifts in Egypt, a staunch US ally for decades.
But it has now answered the perennial question – should Washington prioritize Cairo's strategic weight or ostracize it over human rights by offering an invitation to Obama's Africa summit next month, after freeing up millions of dollars in military aid.
Elsewhere, administration policies have mystified some allies.
He might be a questionable witness, but former vice president Dick Cheney is highlighting discontent among US allies to repair his own checkered regional legacy.
US friends in the region were "wringing their hands" at their inability to trust Washington, Cheney said at a Politico lunch on Monday, bemoaning the administration's failure to halt the march of Islamic radicals across Syria and Iraq.
Saudi Arabia made its displeasure at Obama's arms length policy towards the region clear meanwhile through articles by prominent figures in global newspapers, and won a visit from the president to reassure King Abdullah in March.
Bahrain, where the US Fifth Fleet is headquartered, caused a stir last week when it threw out a top State Department's human rights envoy.
Washington's closest Middle East ally, Israel, while preoccupied with the Gaza crisis, never fails to voice skepticism over Obama's drive for a nuclear deal with Iran.
But the success of the US-developed Iron Dome umbrella shielding Israelis from Hamas rockets has defused Republican claims Obama has "abandoned" the Jewish state.
The ironies of the new Middle East meanwhile are multiplying.
Washington finds itself lining up alongside foes Iran and Syria rooting against Islamic State radicals in Iraq – while seeking the ouster of President Bashar al-Assad in Damascus and disdaining Tehran's regional powerplays.
Friendships warm in Asia
But American friendships are prospering in Asia, where Washington has exploited unease at China's brawny maritime claims.
Obama's pivot to the rising region is anchored on reinvigorating alliances with Japan, South Korea, the Philippines and Australia.
Washington has also drawn out Malaysia and weaned Myanmar away from China.
A senior Asian diplomat said the region was reassured by Obama's visit in April when he cemented US defense guarantees to Japan and clarified when Washington would defend the Philippines.
But China, which frets about strategic encirclement, views US troop rotations through Australia and the Philippines and American naval maneuvers with suspicion -- raising the prospect that Washington's courting of regional allies could worsen its rivalry with Beijing.