President Obama and Europe were bound together during his first two years in office by the global economic downturn and the collective effort to resolve it. But the dominant themes of the president’s European tour, set to begin Monday, highlight how much the world has changed over that time.

As he enters the second half of his term, security issues, in South Asia and the broader Middle East, have replaced the economy as the chief shared interests of the world’s wealthiest and most powerful allies.

The war in Afghanistan, the stalled rebellion in Libya, the crackdown in Syria and the wider implications of the changes emerging from the Arab Spring will occupy a large portion of the president’s time as he travels from Ireland to Poland over six days.

The world economy, recovering at different paces in different regions, has slipped from its boldface top spot on the transatlantic agenda. In detailing the upcoming Group of Eight summit in France, one French diplomat last week listed the economy as Part B of Topic 3 — following “freedom and democracy” and “peace and security.”

Leavened by a few cultural stops, including a likely pint of Guinness with distant relatives in Moneygall, Ireland, Obama’s meetings and public remarks will be guided by issues of war and peace on a continent that has at times felt squeezed out by this president’s attention to Asia.

Part of his goal, according to advisers and analysts, will be to underline the central importance of Europe and the alliances there that Obama pledged to reinvigorate on taking office. His promise served as a break from the previous administration, which pointedly divided the continent into “old Europe” and the newer democracies of Central and Eastern Europe that more fully supported U.S. counterterrorism strategy.

“Maybe this is an overstatement, but I see this as an opportunity for a reset of the European relationship,” said Heather A. Conley, director of the Europe Program at the Center for Strategic and International Studies. “European leaders have really been struggling with where they fit. They had enormous expectations for this president, but they’re now wondering, ‘Is it that different after all?’ ”

Obama’s first trip to Europe in the spring of 2009 was marked by his celebrity and the world’s economic peril.

He was greeted at the Group of 20 meeting in London as a star, and fellow world leaders clamored to be seen with him. Eight years of the administration of George W. Bush, whose often unilateral approach to many policies, including the decision to invade Iraq, had alienated many European leaders and publics.

Obama promised a return to partnership, through NATO, the G-8 and G-20, and the European Union.

His senior advisers say he has managed to remake the U.S. relationship with Europe by working through the global economic crisis, expanding the war in Afghanistan with European support and, most recently, by moving against Libyan leader Moammar Gaddafi with a NATO-led military effort.

“This trip very much underscores the extent to which he has achieved that with our closest allies and partners in Europe,” said Elizabeth Sherwood-Randall, the National Security Council’s senior director for European affairs.

But European diplomats and analysts say Obama will have some relationship-patching to do, especially in Eastern Europe, where fears of the president’s “reset” relationship with an unpredictable Russia raise concerns about his commitment to their security.

And Europe’s credit crisis, which has led to drastic belt-tightening in Britain and other countries, has also made some allies less able or willing to follow Obama’s lead.

The retrenchment comes as Obama will be asking European countries to continue to lead the military effort in Libya, remain in Afghanistan and give more to support democratic change in the Middle East and North Africa.

“Europe is a much different partner than when he came into office,” Conley said. “There’s a realization that Europe is under great strain and that they will not, automatically, be willing to follow America’s lead.”

Obama lands Monday in Dublin for a largely ceremonial visit to a nation with strong, often personal connections to the United States. He will meet with Irish President Mary McAleese and deliver a speech celebrating those immigrant ties in a country whose once-fiery economy has crashed hard in recent years.

The personal highlight will be Obama’s short visit to the one-stoplight village of Moneygall, population 300. Records show that Obama’s great-great-great-grandfather on the side of his mother, Ann Dunham, may have been raised in Moneygall before heading to the United States in 1850 at age 19.

“It’s certainly quite likely that in a town of that size, that is so deeply rooted in that part of Ireland, that there are people who share those ties,” said Ben Rhodes, the deputy national security adviser for strategic communications, on whether Obama planned to meet relatives there.

‘The anchor speech’

During his next stop in London, a visit that begins with a meeting with Queen Elizabeth II, Obama will speak to Parliament about the American relationship with Britain and Europe. Rhodes called it “the anchor speech” of the trip.

In his meetings with Prime Minister David Cameron, administration officials and British diplomats said topics will include political change sweeping the Middle East, the enduring military campaign in Libya and the imminent drawdown of U.S. and British troops in Afghanistan.

Several European diplomats said Obama will likely hear requests from NATO partners, most notably Cameron and French President Nicolas Sarkozy, to deploy more strike aircraft to the Libya campaign, now targeting Gaddafi’s command-and-control structure.

Regarding Afghanistan, the focus will be on shifting from a military effort to a political process with the Taliban.

Obama has said he will begin withdrawing in July some of the 30,000 additional troops he deployed to Afghanistan at the end of 2009. Nigel Sheinwald, the British ambassador to Washington, said Britain hopes “to be reducing its forces responsibly in the period ahead as well.”

As a result, he said, Cameron in his meeting with Obama will be seeking a “vigorous political track, which means putting more effort in the months ahead into the prospects for reconciliation, discussion, leading to eventual negotiations with the Taliban.”

“We agree with this administration that the Taliban are part of the fabric of Afghan society, and we’re going to need to deal with them, and reach a settlement with them, and with other parties to Afghanistan’s future, in order to have a secure transition,” he said.

In Deauville, France, the next stop, Obama will attend the G-8 summit and meet on the sidelines with Russian President Dmitry Medvedev, Japanese Prime Minister Naoto Kan and French President Nicolas Sarkozy.

The summit will begin with a show of solidarity with Japan, as it struggles to recover from the devastating tsunami and nuclear disaster. The leaders then intend to discuss nuclear safety and ways to ensure that standards are being met globally.

French diplomats say the G-20 summit, scheduled for later this year in Cannes, France, will more fully address economic issues. At the G-8, though, the Arab Spring, as the uprisings across the Middle East and North Africa are collectively known, will occupy much of the meeting.

Some of the discussion will focus on the financial support rich countries can give to those in democratic transition, including debt relief and loan guarantees that Obama announced Thursday for Egypt in his Arab Spring address at the State Department.

The leaders of Egypt and Tunisia, two countries that have toppled long-standing autocrats this year, will attend the summit’s second day. “We expect there to be a broad embrace of an approach to the Middle East and North Africa that includes many of the elements that the president laid out in his speech,” said Michael Froman, the deputy national security adviser for international economic affairs.

Diplomatically tricky

The president’s final stop is Warsaw, where he will have the opportunity to meet with leaders of Eastern and Central European nations there for a summit. The visit is perhaps his most diplomatically tricky of the trip.

Plans for Obama to visit Poland last year, following the plane crash that killed Polish President Lech Kaczynski and dozens of others from the nation’s political and military leadership, was canceled because of ash from the Icelandic volcano eruption. During this visit, he will pay tribute to those killed.

Obama has made a high-profile priority of improving relations with Russia — a key partner in confronting Iran — ensuring supply lines to Afghanistan and preventing nuclear proliferation. But many Eastern European nations fear Russia’s influence, exerted through energy policy and its military, which fought a war with Georgia in 2008.

Obama heightened those concerns early in his administration by changing plans to station 10 interceptors from the Bush-era missile defense system in Poland, a shift in design that many viewed as a concession to Russia.

Administration officials said Obama would discuss with Polish leaders the country’s key role in NATO and the Libya campaign, Russia, and ways to support the democratic transitions in the Middle East and North Africa. The Obama administration has studied Poland’s own transition to democracy as a model.

“The administration has worked very hard since then to get out of that hole,” Conley said. “They have been working on the Central and Eastern Europe relationship, and Poland is obviously the key player in that.”