© AP Photo/Michael KappelerPresident Obama and German Chancellor Angela Merkel at the Brandenburg Gate in Berlin.
After the rebalancing of US diplomacy towards Asia, Mr Obama is also facing the challenge of sustained re-engagement with the continent's leaders, who often felt neglected in his first term and, more recently, bruised by allegations of US espionage.
Mr Obama will spend three days in The Hague and Brussels, at a summit of G7 leaders in the Dutch city, followed by a visit to Nato headquarters and a meeting with the EU. The overriding focus will be how to fashion and hold together a tough line against a Russian leader whose lightning incursion into Ukraine has startled the west.
So far, the US has responded with a series of sanctions against some of Mr Putin's closest associates ahead of the meeting at The Hague, taking place alongside an already scheduled nuclear security summit.
But Mr Obama's pushback against Moscow has been too little and too late, according to former administration advisers, and has failed to match the tough rhetoric from the White House about the Crimean takeover.
The administration has attempted to construct a set of sanctions that can be scaled up depending on Mr Putin's actions, especially if Russian troops make further incursions into Ukraine.
"But there has been a mismatch between what the administration has been saying and what they have been willing to put behind it," said one former Obama adviser.
The White House more generally faces criticism that Ukraine is a symptom of a wider issue: its foreign policy team's weakness in preparing for potential crises.
"They keep being surprised by the unsurprising and are unprepared for things they should have been prepared for, including the consequences of their own actions or, as often, inaction," said David Rothkopf, of Foreign Policy.
Adding to Mr Obama's problems is the fall in his standing at home since the botched rollout of his signature health reform plan, and any missteps abroad will only compound his domestic difficulties.
"Everything is much more fraught with foreign policy. There will be no more speeches at the Brandenburg Gate," said another former adviser.
Ukraine's crisis has opened up some traditional policy fissures in Washington between Mr Obama's political and economic advisers.
Economic officials have broadly cautioned against tough sanctions because of the potential blowback against a US economy still struggling to regain solid growth, while Mr Obama's political advisers have pushed for tougher action, because of the diplomatic principles at stake.
The administration also has a loose split between cabinet members and officials who promote a more activist global role for the US, such as Susan Rice, the national security adviser, Samantha Power, the UN ambassador, and also John Kerry, the secretary of state.
They can run up against Mr Obama himself and Joe Biden, the vice-president, who have expended considerable energy in disentangling the US from old conflicts, and limiting its involvement in new ones.
Mr Obama's instinct has been firmly aligned with public opinion, with the latest NBCWall Street Journal poll showing striking numbers of Americans opposing greater US involvement in global politics.
Only 23 per cent of people polled said they would be more willing to vote for a candidate advocating the US do more to resolve conflicts around the world. Nearly one in two respondents said they would be less likely.
"This data is really powerful signal about a country that is fatigued," said Bill McInturff, of Public Opinion Strategies, a leading polling company.
"The attitude is, 'let someone else mind the store - we have had it'."
However, Russia's takeover of Crimea is forcing a rethink of the administration's policy towards Moscow, and perhaps further.
"What we have seen in Ukraine is obviously a very egregious departure from [international norms], and it is causing the countries and people of Europe and the international community, and of course, the US, to reassess what this means," Ms Rice said on Friday.
Mr Obama is taking the opportunity in The Hague to convene a meeting between America's two key north Asian allies, Japan and South Korea, whose relations have been frozen by a revival of historical disputes.
Shinzo Abe and Park Geun-hye, the Japanese and South Korean leaders, have not met since Ms Park was elected in February last year, despite persistent US efforts to prod them to talk.
Mr Obama will also visit Brussels, Rome, where he will meet the Pope, and Saudi Arabia, where relations have been frayed by US negotiations with Iran, before returning to Washington on the weekend.
Comment: Coming to her senses: Merkel not ready to back economic sanctions against Russia