Chris Cillizza takes a look at the polling and sees an improbable John McCain summer run at Barack Obama.  With almost all eyes focused on Obama’s campaigning in Europe, McCain has moved within the margin of error in three key states, two of which went to the Democrats in 2004.  The results show that Obama may be far weaker than anyone imagined:

Republican John McCain has quickly closed the gap between himself and Democratic rival Sen. Barack Obama in several key battleground states even as the Arizona senator struggles to break through the wall-to-wall coverage of Obama’s trip to Europe and the Middle East this week.

McCain and Obama are in a statistical dead heat in Colorado, Michigan and Minnesota while the Illinois senator has a more comfortable double-digit edge in Wisconsin, according to polling conducted by Quinnipiac University for washingtonpost.com and the Wall Street Journal during the past week. Only in Colorado, however, does McCain hold a greater percentage of the vote share than Obama.

McCain went ahead of Obama in Colorado for the first time in weeks, with a seven-point swing in just a month.  In Minnesota, where almost everyone expects Obama to win by at least the 3.5% margin John Kerry enjoyed in 2004, a fifteen-point swing has brought McCain within two points of Obama.  Michigan has moved to the margin of error, with McCain gaining nothing but Obama losing two points.  Only in Wisconsin, which had been a slender Democratic state in 2004, has Obama maintained his lead.

This bodes ill for a campaign that has the attention of the nation.  Obama, with the avalanche of media coverage given to his historic nomination and his trip abroad, should be creaming McCain in the polls at this point.  However, McCain has managed to not just keep pace but to gain ground, and most importantly to maintain a slight advantage among independents.   Only in Colorado does he have less-favorable numbers among independents than Obama, and in Minnesota Obama can’t clear a majority favorable rating — a big surprise in a more-or-less progressive state.

Cillizza looks at the issues polling and believes he sees the reason for the shift:

One possible reason is the campaign’s focus over the last month on the war in Iraq and national security concerns more broadly. McCain’s campaign has hammered home the idea that Obama was mistaken in his opposition to the surge of U.S. troops last year and is wrong now about his proposed 16-month timetable for withdrawing troops.

Voters in all four states seem to agree. Asked whether they would prefer a “fixed date” for withdrawal or to “keep troops in Iraq until the situation is more stable,” majorities in all four states preferred the latter option despite the fact that similar majorities in each state say that America was wrong to go to war in Iraq.

Another reason would probably be energy.  McCain has spent the last couple of weeks hammering Obama on his refusal to drill for more oil in response to the supply crisis that has sent fuel prices skyrocketing.  That issue plays against Democrats in general, and the more McCain focuses on this, the better Republicans can do in the fall.   Offshore drilling gets large majorities in support in all four states, between 59% and 63%, and by large margins voters believe energy policy to be more critical than Iraq.  Obama’s intransigence on it could do a lot of damage this fall down the entire Democratic ticket.

Update (AP): One further note to Ed’s post. Here’s the data on withdrawal from the Quinnipiac poll in June, which I blogged about at the time:

And here’s the same question in the new poll:

It’s within the margin of error, but note that the poll was taken from July 14 to July 22. Maliki’s timetable comment hit the wires on July 19. No effect?