The Ukraine crisis has brought the EU and the US together; the US has offered gas supplies to help decrease European dependence on Russia, which is supposed to understand the message.
Belgian police have plenty of experience with major summits - the European Union holds meetings in Brussels every few weeks. But it's something different when the President of the United States turns up - then it's the US Secret Service which takes control. Corrugated iron huts are built on roofs for reconnaissance personnel and sharpshooters. Streets and squares for some distance around the meeting point are closed, bus routes are diverted, even the trash bins in distant subway stations are screwed shut. Obama is guarded by 1,500 police, and the people of Belgium don't get to see him as he makes his first visit to the capital city of Europe.
Best friends still
This is the first official summit between the EU and the US since 2011. Obama wants to allay fears in Europe that he doesn't really take the old continent seriously.
"Europe, including the European Union, is the cornerstone of our engagement around the globe," said Obama at his press conference. "We are more secure and we are more prosperous, the world is safer and more just, when Europe and America stand as one."
That pleased EU Council president Herman Van Rompuy, who emphasized US reliability in the face of the current tensions with Russia: "It is the bedrock to face these challenges, a bond of friendship tested by history, and that bond is shockproof."
The summit was not much more than a courtesy visit; Obama's talks with Van Rompuy, EU Commission President Jose Manuel Barroso, EU foreign policy chief Catherine Ashton and EU trade commissioner Karl de Gucht lasted just under two hours, including lunch.
When the summit was planned, no-one could foresee the conflict with Russia over Ukraine, says Jan Techau of the Carnegie Foundation in Brussels, but that has unexpectedly welded the Europeans and the US together: "It's interesting to see how, at a time of existential crisis, the core of the transatlantic relationship becomes visible - and that's the security partnership."
Barroso chose emotional language to issue what was almost a passionate appeal: "I'd like to say to the American people that you can count on us as your best friends and allies."
Stay cool about the trade agreement
Controversial issues such as the NSA spying scandal were kept in the background. The two sides are more concerned to get the transatlantic trade agreement TTIP on the road. But they're leaving the details of consumer and data protection to the negotiating teams.
"There's no point in getting excited about potential provisions in trade agreements which haven't been drafted yet," said Obama. There'll be plenty of time for that later. But he wanted to reassure people: "I guarantee you we are going to be working hard to make sure that environmental protections and consumers protections that are already in place, that those are strengthened."
The European Parliament has to approve the TTIP, and resistance to certain provisions is growing there. One liberal member of the parliament, Alexander Graf Lambsdorff, who experienced the US as a German diplomat there, says the US has as much interest in free trade as the Europeans.
"We should use that fact strategically," he says. "The EU and the US have to agree on common standards on data protection. That's got to be achieved at the same time as the trade agreement - it would be the wrong signal to suspend the talks now."
Van Rompuy sees the trade agreement as a strategic instrument to isolate Russia even further in the current crisis: "In days like these, forging even stronger economic ties across the Atlantic is also a powerful political sign - a way to show our public opinions and the world who we are at heart in Europe and in America. Economy is based on rules; society is based on values, and proud of being so."
More American gas for Europe
The US and the EU want to see if Europe can become less dependent on Russian energy supplies. Obama announced that the US wanted to put more gas on the world market in order to compete with Russia. But he also said that Europe must do more to exploit its own sources. Fracking - the extraction of gas from rock formations - is widespread in the US, but controversial in the EU.
Disagreement on that point didn't prevent unity on the main issue of the day: "If anyone in the Russian leadership thought the world wouldn't care about their actions in Ukraine, or that they could drive a wedge between the European Union and the United States, they clearly miscalculated," said Obama. "If Russia continues on its current course, however, the isolation will deepen. Sanctions will increase and there'll be growing consequences for the Russian economy." The EU and the US were in complete agreement on that, and Obama said that NATO would be considering a permanent increase in its military presence in those of its Eastern member states which had borders with Russia.