WASHINGTON — After months of caution, President Barack Obama suddenly is positioned more aggressively on Syria than the global leaders he's joining at a summit Monday, now that he has authorized weapons and ammunition shipments to struggling rebels.
Obama is expected to push Britain and France to take similar action when talks open in Northern Ireland among the Group of Eight leading industrial powers. The U.S., Britain and France also will urge Russian President Vladimir Putin to drop his political and military support for Syrian President Bashar Assad, still in power after more than two years of fighting.
"It's in Russia's interest to join us in applying pressure on Bashar Assad to come to the table in a way that relinquishes his power and his standing in Syria," said Ben Rhodes, Obama's deputy national security adviser. "We don't see any scenario where he restores his legitimacy to lead the country."
Obama and Putin plan separate talks on the sidelines of the summit, in what would be their first in-person meeting since Obama' re-election last November.
Russia analyst and Georgetown University professor Angela Stent said Putin probably will try to draw a distinction with Obama on Syria by portraying himself as a "guarantor of the absolute sovereignty of states."
"That may go down less well with the G-8 but has a broader appeal in the rest of the world," Stent said.
Also on the agenda for the two-day summit at a golf resort in Lough Erne are the global economy, a proposed U.S.-European Union trade agreement, and counterterrorism.
Obama will stop first in Belfast, where he will speak to young people about maintaining Northern Ireland's peace with its Irish neighbors. The president will cap his European trip with a visit to Germany for meetings with Chancellor Angela Merkel and a speech at Berlin's Brandenburg Gate.
Questions about the international response to the Syrian civil war seem likely to dominate. For months, Obama resisted calls, both in Washington and from global allies, for greater U.S. involvement, though he said repeatedly that the use of chemical weapons would cross a "red line" and change his calculus.
The White House said Thursday that it had conclusive evidence of the Assad government's use of chemical weapons. In response, U.S. officials said Obama had, for the first time, authorized lethal aid for the Syrian rebel forces. The exact type of weaponry and how quickly it would get to the opposition remained unclear.
Rhodes said Obama would consult on Syria with the G-8 leaders, particularly British Prime Minister David Cameron and French President Francois Hollande. Both countries have indicated a willingness to arm the rebels but are yet to take that step.
"With the French and the British, they have shared our positions generally on Syria," Rhodes said. "He'll be discussing with those leaders what the best way forward is. He'll hear from them what their plans are."
Still, it appears almost impossible for the G-8 leaders to reach a consensus, given Putin's allegiance to Assad. Russia has called for a political dialogue between Assad and the opposition, but Putin has not called for the Syrian president to step down and opposes foreign military intervention.
Russia's foreign minister said Saturday that the U.S. evidence of chemical weapons apparently didn't meet stringent criteria for reliability. Sergey Lavrov also scoffed at suggestions that Assad would use such weapons now in light of its apparent growing advantage against the rebels. "The regime doesn't have its back to the wall. What would be the sense of the regime using chemical weapons, moreover at such a small quantity?" Lavrov said.
Secretary of State John Kerry told Iraq's foreign minister in a telephone call Friday that Assad's use of chemical weapons and the "increasing involvement" of Hezbollah fighters backing Assad threatens "to put a political settlement out of reach," according to the State Department.
Obama and Putin also will discuss missile defense and U.S. calls for further reductions of both countries' nuclear stockpiles. These issues have exposed a deep mistrust between the U.S. and Russia, and there is no expectation of a breakthrough.
The leaders will talk about counterterrorism cooperation following the April bombings at the Boston Marathon. The two brothers suspected in the attacks are ethnic Chechens who lived in the U.S. for more than a decade. Russia asked the U.S. to investigate the older brother before the attacks, but it's unclear what type of information Moscow provided, particularly related to his six-month stay in the Russian region of Dagestan before the bombings.
In Europe, Obama will be seeking a reprieve from the domestic controversies that have diverted attention from his second term agenda. They include the Internal Revenue Service's targeting of conservative political groups; the resurgent investigation into the deadly attacks on Americans in Benghazi, Libya; the Justice Department's seizure of phone records from journalists; and most recently, revelations that the National Security Agency has been broadly monitoring U.S. phone and Internet records.
The debate over the NSA programs may follow Obama to Western Europe, where privacy laws are stricter than in the U.S. A German government spokesman has said that Merkel will question Obama about the programs.
"The Obama administration will face some awkward conversations in Europe," said Michael Geary, a fellow at the Woodrow Wilson International Center. "Europeans are a little bit miffed on the subject."
Cameron, as the summit host, is pushing an agenda focused heavily on the global economy and trade. He had hoped to announce the launch of negotiations on a broad U.S.-E.U. free trade pact. But those prospects appear to be dimming given French insistence that European film, radio and TV industries be excluded from the negotiations.
The U.S. says nothing should be taken off the table before negotiations even begin.
The other members of the G-8 are Italy, Japan and Canada. Leaders from developing nations, including Libya and Liberia, will join the G-8 leaders at a lunch Tuesday to close the summit.