Reports of a surging McCain are greatly exaggerated. While Obama and McCain are mobilizing supporters and maintaining a close race, the numbers on this most recent ABC/WaPo poll have changed about as much as the other national polls - by a point or two, Obama leading.

Presidential choice RV 8/19-22 (July) (June)

Obama 49 (50) (49)

McCain 43 (42) (45)

The Registered Voter numbers (prior to the Biden announcement) are +6 Obama, but WaPo also offers Likely Voter numbers with trends (who is a likely voter this year remains unclear). This is a good example of current LV screens favoring McCain, whose demographic of older voters fits better into LV classification [more on LV's here from Mark Blumenthal]:

Presidential choice LV 8/19-22 (July) (June)

Obama 49 (49) (47)

McCain 45 (46) (48)

As for particulars:

The focus on foreign policy crises over the past month, including the Russian invasion of Georgia, has played to McCain's perceived strengths among the electorate. He holds 2 to 1 leads over Obama in the new poll as the candidate with better knowledge of world affairs and the one who would make a better commander in chief. He is also regarded as superior to Obama in combating international terrorism and has a slender advantage on international affairs generally, the latter thanks to a clear edge among independents. But on the question of who is better equipped to deal with specific foreign policy problems, McCain's advantages are less apparent. Voters rate McCain and Obama evenly on handling the situation in Iraq, and McCain has a negligible advantage in dealing with U.S. relations with Russia. And it is Obama who continues to hold a lead on dealing with the nation's flagging economy, although his margin on that crucial question is somewhat narrower than it was a month ago. Where Obama is strongest is in public assessments of his candidacy and personality. He has a better than 2 to 1 edge as the more optimistic candidate and a 21-point advantage on who would do more to stand up to special interests. Although both candidates have tried to stress their desire to govern in a bipartisan fashion, voters by a 12-point margin see Obama as the one more likely to work cooperatively with Republicans and Democrats in Congress.

Usual enthusiasm gap:

Nevertheless, McCain's candidacy cannot match Obama's on enthusiasm. More voters are enthusiastic about Obama's run than McCain's, and while almost all of those who support a candidate are enthusiastically behind their pick, Obama's backers are about twice as likely to call themselves "very enthusiastic," 52 to 28 percent.

This is a bit different, though:

As for the general tenor of the campaign, about two-thirds, 64 percent, said Obama is primarily focused on addressing the issues; 45 percent said so of McCain. On McCain's campaign, about as many, 48 percent, said he was instead mainly focused on attacking Obama.

Our friends, the ex-Republicans:

Independents overall remain about evenly split in their vote preferences: 45 percent support Obama, 43 percent McCain. Each candidate garners an identical 59 percent favorable rating from independents, underscoring some voters' tough choices ahead.

Separately, Polling Report has a good summary of the Biden reaction with the voters. Between Fox and ABC/WaPo polls, the Biden choice makes no difference among 75% of responders (ABC/WaPo), and is a wash among Fox responders (Dems like the choice 3:1, opposite with the GOP). [Gallup and Rasmussen agree, but note that older voters like Biden, complementing Obama's appeal with younger voters.]

Bottom line is that, for now, the electorate remains polarized. Perhaps the best way (and maybe the only way) to break through is to elect a Democrat and show they can govern effectively. If the election were held today (and it won't be) the polls suggest that is what would happen, particularly if new and younger voters show.