LONDON — Barack Obama conquered the Middle East and Europe last week, but yesterday he returned to face a more challenging battleground: middle America.

Obama, the presumptive Democratic presidential nominee, wrapped up his weeklong overseas tour with an acknowledgment that — for all the television coverage his travels from Afghanistan to Britain received — he was anxious to get back to domestic issues.

"We've been out of the country for a week," he said outside the British prime minister's official residence at 10 Downing St. "People are worried about gas prices. They're worried about home foreclosures."

Obama aides said they believed the unusual trip succeeded in bolstering the first-term Illinois senator's credibility as a potential commander in chief despite his brief tenure in national politics.

"Any campaign, in part, is about whether people can picture a candidate in that role," said David Axelrod, Obama's chief strategist.

U.S. political analysts, including many Republicans, largely agreed — but added it was too early to measure the impact of the trip.

"Obama had a historic week. He cleared all the bars and did amazingly well," said Scott Reed, who managed the 1996 presidential campaign of Republican Bob Dole. "But it probably isn't going to change many votes. ... He still hasn't closed the deal."

"It would be hard to come up with a better week for Obama," said Christopher F. Gelpi, an expert on public opinion at Duke University. "But it will be another week or so before we see if he got a bounce."

Polls conducted while Obama was on the road produced conflicting results. As of yesterday, the Gallup daily tracking poll found that the Illinois senator had gained a few points and led Sen. John McCain, R-Ariz., nationwide, 48 percent to 41 percent; a Fox News Poll released Thursday found that Obama had slipped a few points and had a statistically insignificant edge over McCain, 41 percent to 40 percent.

Neither poll suggested a change in the dilemma Obama's trip sought to address: Most voters prefer the Democrat's positions on the economy and other domestic issues, but most believe McCain is more qualified to be president, especially as a leader on national security.

Obama aides said they intend to turn their campaign's focus back toward the domestic economy beginning tomorrow, after their candidate spends today in his hometown of Chicago following a his roughly 16,000-mile journey.

McCain, too, is seeking to build an advantage on a domestic issue: energy. Polls show that most voters agree with McCain's positions in favor of increased drilling for offshore oil and building new nuclear power plants. Yesterday, McCain criticized Obama for opposing both.

As political theater, Obama's trip was an epic. It displayed him in photogenic locations meeting troops at U.S. military bases in Afghanistan and Iraq, praying at Jerusalem's Western Wall and speaking to a huge, cheering crowd in Berlin — complete with American flags distributed by the candidate's campaign aides.

Obama provoked not only the customary polite reception from most foreign leaders but an effusive embrace from France's President Nicholas Sarkozy, who said: "If he is chosen, then France will be delighted."

More important, and perhaps more helpful to Obama's presidential chances, were the virtual endorsements he received from leaders of Iraq and Israel for his most controversial foreign policy positions.

In Iraq, Prime Minister Nouri al-Maliki said he favored an early withdrawal of U.S. combat troops and called Obama's proposed timetable of 16 months from January 2009 "suitable."

After pleas from the U.S. Embassy, al-Maliki's spokesman softened the statement, but only a little: He said the Iraqi government favored a withdrawal by the end of 2010.

The Bush administration and McCain have opposed setting a fixed timetable, although the White House has agreed to discuss a "time horizon" based on military conditions. And by the end of the week McCain endorsed that idea, too.

In Israel, Prime Minister Ehud Olmert and other officials praised Obama for his understanding of their country's concerns; they especially lauded his strongly worded assurance that he considers it unacceptable for Iran to acquire a nuclear weapon.

Obama aides said they spent months on groundwork for the trip, including conversations with Israeli officials explaining his positions on Iran and other issues.

The trip was not flawless. There were gaffes ranging from verbal slips (Obama declared that "Israel is a strong friend of Israel's") to the last-minute cancellation of a planned visit to a U.S. military hospital in Germany. And some critics scorned Obama's speech in Berlin as more poetry than substance.

But even GOP political operatives viewed the journey as a technical success, if only because it enabled Obama to dominate campaign coverage.