Six days into Barack Obama's international tour, the Gallup daily tracking poll shows the race for president remains tight, with only two points separating the presumptive nominees, 45% to 43%, on combined data from July 21-23. Odd.

Everything has gone well for Obama on this foreign excursion, and McCain spent the week floundering from gaffe to gaffe, while his campaign portrayed an immature, petulant tone toward the positive coverage generated by the senator from Illinois.

So this begs a question: Why so close? Shouldn't Obama be wiping the floor with this guy? (Sure, he was up on McCain by 10 points in one Newsweek poll in June, but nobody believed it and it didn't last.)

Friday morning, NPR reported that McCain's numbers had recently ticked upward in four key battleground states, Michigan, Wisconsin, Minnesota and Colorado. These state-by-state numbers are really more significant than the national overall figure. After all, the fall presidential election is not a national popular vote election, not a plebiscite, but rather 50 different elections (plus the District of Columbia.)

Enter Hillary Clinton. For Democrats, she's apparently like morning sunshine.

A new Opinion Dynamics poll taken for Fox News tells the tale, but Fox News buried it. All they report on their website is the data showing "No Bounce For Obama from Overseas Trip," but question #3 in the poll, shows Obama's slim lead increases substantially with her on the ticket.

The survey, taken Tuesday and Wednesday of this week among 900 registered voters, shows Obama beating McCain by a statistically meaningless 1 point in a two-way race, and 3 points if the Independent Nader and Libertarian Barr are tossed in.

However, a mythical matchup of Obama-Clinton beats a Republican ticket of McCain-Romney by 9 points, well outside the 3 point margin of error. Opinion Dynamics polling has shown the same thing for three straight months now.

This suggests that the tightness in the race is due to voter uncertainty on the Democratic side of the draw.

Remember: throughout the winter and spring, it was Democrats who told pollsters they were overwhelmingly happy with their choices, while Republicans were overwhelmingly bummed about theirs. Things have not changed, which is why repubs stay sour when offered McCain-Romney, and Obama's numbers suddenly brighten when paired with her.

He's done the job on the trip abroad. He's looked and spoken presidential, and it must have been heartwarming for every American to actually see U.S. flags waving proudly in the throng of 200,000 Germans in Berlin. When was the last time Europeans waved Old Glory without lighting it on fire?

The final piece to the puzzle may well be adding Clinton's populist economic message to Obama's call for "change we can believe in." She racked up big primary wins in states loaded with electoral votes (Ohio, Pennsylvania, Florida, etc.), and she and Obama finished the nominating season in a virtual tie in popular votes cast.

The solution may be that simple. She's got "huge tracts of land," as noted in "Monty Python and the Holy Grail." It seems Democrats don't just need them, Democrats desire them.