A European Commission official said Bush's arrival itself is a message that the United States is ready to reach out to Europe. He said that whereas Bush's first term had been starkly unilateralist, there now exist signs that a substantial rapprochement is possible.
The United States has tried to reciprocate in recent days. One of the clearest signals concerns Iran, widely recognized as potentially the most explosive issue on the trans-Atlantic agenda.
When U.S. Secretary of State Condoleezza Rice visited Europe two weeks ago, she was ambiguous when asked about U.S. plans. She appeared to cast doubt on the ability of Britain, France, and Germany to negotiate an end to Iran's uranium-enrichment program. A U.S. attack, she said was not on the agenda, adding the caveat at this point.
In an interview to the Belgian TV channel VRT over the weekend, Bush appeared to come out strongly in favor of diplomacy.
"You never want a president to say never, but military action is certainly not, is never the president's first choice," Bush said. "Diplomacy is always the president's -- or at least my -- first choice."
Officials in Brussels say EU leaders will be hoping to extract a promise from Bush for a more active and constructive engagement with the bloc's negotiating effort with Tehran.
Overall, EU officials say, they hope to focus on what unites the bloc and the United States, rather than what sets the two parties apart. According to one European Commission official, the emphasis will be on "how to best do things together in the world."
The official said the EU will stress that both sides share the same common values, such as democracy, rule of law, and human rights.
The comments appear to take their cue from Rice's speech in Paris two weeks ago, where she said that "only enemies of freedom" would benefit from trans-Atlantic divisions.
But, the official said, the EU also has its own interests to protect and its own institutions to promote -- a reference to Washington's perceived lack of enthusiasm for further EU integration.
Bush's visit falls into three parts. Today, he will hold meetings with Belgian leaders and then have dinner with French President Jacques Chirac. Tomorrow, he will first attend a NATO summit -- attended by Ukrainian President Viktor Yushchenko. He will then meet all 25 EU heads of state and government. Later, he will travel to Mainz, Germany, and from there to Bratislava, Slovakia, to meet with his Russian counterpart Vladimir Putin.
Bush said over the weekend he hopes to tackle a wide range of global issues in which he sees many opportunities to make progress.
"Over the last several weeks the world has witnessed momentous events -- Palestinians voting for an end to violence; Ukrainians standing up for their democratic rights; Iraqis going to the polls in free elections. And in Europe, I will talk with leaders at NATO and the European Union about how we can work together to take advantage of the historic opportunities now before us," Bush said.
The EU has designated "lead speakers" to address different topics trying to make the best use of the 90-minute meeting. Thus, Chirac will speak on EU integration, British Prime Minister Tony Blair on the Middle East, and German Chancellor Gerhard Schroeder on Iran. Slovakia was picked as the lead nation to present EU policy on Iraq, Ireland on Brussels's take on Russia, and Hungary will advise on the EU's policies toward Ukraine.
One NATO diplomat told RFE/RL last week that Bush's main request to the alliance is to find personnel and funds to train Iraqi security forces. As of 18 February, NATO still needed 27 of the 159 instructors it will commit to that task.
The EU this week will approve its own "rule of law" mission to help Iraq build up its criminal justice and law-enforcement system. The mission should become operational in July, but all training will take place outside the country.
One potentially divisive issue is the EU's intention to lift its weapons embargo on China. This causes major concerns in Washington and Bush will put pressure on EU leaders to drop the plan. However, he is unlikely to succeed.
Other potential stumbling blocks include trade issues and climate change. EU officials said last week, however, that they were not hoping to get the United States to sign up to the Kyoto Accord on cutting greenhouse gas emissions.
The EU will also ask the United States to initiate moves to remove the visa requirement for citizens of the new member states.