Even in a more-normal week, the Republican candidate might have had trouble commanding voters' attention. Analysts agree that the presidential campaign is primarily about Obama - about whether an electorate unhappy with the status quo and ready for change can get sufficiently comfortable with his background and his resume to vote for him.
An NBC News/Wall Street Journal Poll out last week found that 51 percent of Americans are focused on what kind of president Obama would be, compared with only 27 percent for McCain.
It's too early to know how Obama's journey to the war zones, the Middle East, and western Europe will impact voters' assessment of a prospective Obama presidency. The latest round of polls, though, held out some promise for McCain.
None had him in the lead; he's been four or five percentage points down, on average, ever since Obama wrapped up the Democratic nomination. But McCain is very much within range.
Polls taken while Obama was overseas show no widening of the gap. Indeed, in surveys done by the Quinnipiac Polling Institute before and during the trip, McCain was making headway in Michigan, Colorado and Minnesota, key states all.
A new Rasmussen Poll in Pennsylvania, the first statewide survey in more than a month, had Obama ahead by a hardly insurmountable six-point margin.
And the McCain campaign, though struggling for national attention, got largely glowing local coverage of its time spent in Maine, New Hampshire, Pennsylvania, Ohio and Colorado.
The Republicans hope that doubts about Obama's national security credentials, which the overseas trip was designed to address, turn out to be his fatal flaw. On a conference call last week, Rep. Heather Wilson (R., N.M.) labeled him "frighteningly inexperienced" in that regard.
Obama said that voters' reservations are not surprising.
"It's the devil you know know versus the devil you don't," the Illinois senator told NBC's Brian Williams in one of the interviews he did with the network news anchors who followed him on part of his journey. "But I think the American people understand that we're in a time of profound challenge and that we've got to make some significant changes."
For Obama, the overseas tour seemed to have been nearly everything he could have wanted, at least in political terms. Wherever he went, he was received almost as though he were already president, even though some critics, McCain included, suggested the Berlin rally was inappropriate for a mere candidate.
The stop in the Middle East, aimed in part at addressing reservations among Jewish voters, went off without a hitch, with Obama making a commitment to defend Israel and prevent Iran from obtaining nuclear weapons.
Less pleasing to Obama were questions he kept getting about Iraq, the second stop on his trip.
On Iraq, he struggled to explain the precise meaning of his 16-month timetable for the removal of U.S. combat troops from Iraq. He said that he refused to "get boxed into what I consider two false choices" - the first being to ignore developments on the ground in pacing the withdrawal and the second to be guided entirely by them.
And he took heat from a clearly irritated McCain over his refusal to describe the surge strategy as a success, although Obama acknowledged the reduction in violence and gave the bulk of the credit to the U.S. military.
"Sen. Obama said just this week even knowing what he knows today that he still would have opposed the surge," said McCain, an early and fervent advocate of the surge, on Friday in Denver. "In retrospect, given the opportunity to choose between failure and success, he chose failure. I cannot conceive of a commander in chief making that choice."
In one interview, McCain created controversy of his own by defining the surge so broadly - and inaccurately, in the view of his critics - as to include virtually every positive development in Iraq during the last two years, including some that occurred before President Bush sent the additional troops.
McCain pressed the issue to the point that Sen. Chuck Hagel (R., Neb.), who accompanied Obama to Iraq and Afghanistan, called on both candidates to stop dwelling on the past.
"We're done with that," Hagel said. "How are we going to project forward?"
On the trail, the McCain campaign continues to be haunted by what has come to be known as the "enthusiasm gap." In Wilkes-Barre, he spoke before a half-empty auditorium, even though the event was open to the general public.
Much of the problem has to do with the unpopularity of Bush. But McCain, while playing up his record of working with Democrats in the Senate, has not gone out of his way to distance himself from the incumbent, except on past policy in Iraq.
For both candidates, the pace of the campaign is soon to quicken.
In a week or two, before the start of the Olympics, one candidate, perhaps both, is likely to name his running mate.
In a month, it will be convention season; in two, time for the debates.
Three months from now, the race will be in the home stretch. And voters likely will be focused more on the candidates and the economy than on the lingering images of one fascinating week in July.
Contact senior writer Larry Eichel at 215-854-2415 or firstname.lastname@example.org.