President Obama leaves Saturday night for what may be the most challenging two days of summitry of his presidency. While in Germany, he will try to keep the allies united in a tough response to Russian aggression in Ukraine, assure both Western Europe and Asia that he can deliver on his trade promises, and look for a way to regain the initiative in the ongoing battle against terrorism in the Middle East and Africa.

Before he returns to Washington on Monday night, he also will meet with the embattled leaders of Iraq and Nigeria, both of whom have been rocked by terrorist attacks and are going to Germany looking for more help from the White House. And even before he can meet the other leaders, he'll be doing some badly needed fence-mending with a German public that once adored him but remains angry at the United States after disclosures of U.S. spying on Germany and its leaders. All this will play out on the edges of the annual summit of industrialized democracies, the G-7.

Of course, this used to be the G-8. But for the second straight year, the eighth leader—Russian President Vladimir Putin—was not invited. And for the second straight year, his blatant invasion of Ukraine and continuing occupation of Crimea are at the top of the summit agenda. With the European Union countries facing a decision later this month on renewing the tough sanctions imposed on Russia a year ago, this meeting in the Bavarian Alps resort of Schloss Elmau gives Obama a chance to make sure allied solidarity has not weakened over the past 12 months.

The prime mission of the summit, said Jeremy Shapiro, a former member of the State Department's policy planning staff in Obama's first term and now a fellow at the Brookings Institution, is to demonstrate "solid trans-Atlantic solidarity" on the question so that "there is not any room for the Russians to weave in between them."

Heather Conley, director of the Europe Program at the Center for Strategic and International Studies, said the leaders will have to address the long-term questions as well. "Mr. Putin believes he has survived the worst of this crisis," she said. "So what's next? What's the next plan?" According to the White House, the plan is to stay the course even while acknowledging growing concern about the rise in violence this week in Ukraine.

"We believe it's important that Europe is sending a strong signal of the need to continue the strong sanctions that are in place on Russia," said Ben Rhodes, deputy national security advisor for strategic communications. He told reporters that "we have additional tools in our own arsenal" that could be used if Russia escalates the violence. He said this summit "sends a signal to Russia that it will continue to face severe costs to its economy." And it will send a signal that the G-7 countries believe their strategy will be successful long-term.

It will be tougher for the president to send a message of success for his strategy of defeating the Islamic State extremists, particularly after they routed the Iraqi forces holding Ramadi, the capital of Anbar province, last week. Recovering from that embarrassing defeat and strengthening Iraqi forces tops the agenda for Obama's meeting with Prime Minister Haider al-Abadi as well as for Abadi's meeting with the larger summit group.

Rhodes told reporters the leaders will "review progress" in the fight against the Islamic State and will also examine "our efforts to reinforce and train and equip Iraqi security forces as they seek to reclaim territory taken by ISIL, and ultimately to degrade and push ISIL out of territory that it has taken inside of Iraq."

On another issue, the president will face concern on the part of the allied leaders, all of whom are deeply committed to trade negotiations with the United States but now fear Obama may fail in his quest for Trade Promotion Authority from Congress. Without TPA, the leaders know that the president would be unlikely to secure approval for the trade deal with Asia and certainly would lose all momentum in trade talks with Europe. "That would be a disaster for the president's trade agenda and for his foreign policy in the second term," Shapiro said.

Other agenda items include the nuclear negotiations with Iran, climate change—a topic on which Obama and the allies are in agreement—energy, and the global economy. But even before he can sit down for the first summit session, the president will try a little damage control. For that, he will join German Chancellor Angela Merkel at the small Alpine village of Krün, population just under 2,000. He will eat some German food, meet some German volk, and do everything short of yodeling to proclaim the health of the U.S.-German relationship almost three years after disclosure of U.S. spying on its longtime ally.

This is needed, said Conley, because "we see an increasing spike in anti-Americanism, very much due in part to the NSA revelations." She added that "while we tend to view a lot of the impact of the NSA revelations in Europe as subsided, they have not subsided in Germany." Instead, Merkel's political opponents at home have used them to damage her standing because she is so often in agreement with Obama.

Twenty years ago, that may have been a minor irritation. But that was before Germany rose to be what Shapiro calls "the key interlocutor in Europe" for the United States and before Obama and Merkel developed such a strong relationship. She "is a German and a European leader that the U.S. can really work with and who can really deliver," said Shapiro. "Those things have rarely been combined in Europe in recent years."

Such close ties can be problematic for Merkel, said Shapiro "because the United States has rarely been as bad an odor with the German public as it is today." Oddly, though, while Obama's popularity in Germany has declined from 2008 when he gave a dramatic and acclaimed campaign speech in Berlin, he remains highly regarded by most Germans. "So," said Shapiro, "this is part of a charm offensive."

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