John Zogby usually has good news for Democrats, but not so for Barack Obama.  According to his latest polling, conducted last week, Obama has not just lost his overall lead but has lost ground in core demographics he cannot afford to lose.  Obama lost ground among women, young voters, and 26 points among Catholics:

Barack Obama has lost ground among some of his strongest bases of support, including young people, women, Democrats and independents, according to a new ATV/Zogby poll.

The Illinois Democrat has also lost some support among African-Americans and Hispanics, where his lead over Republican John McCain has shrunk, and among Catholics, where he’s lost his lead.

In other words, he’s fallen back across a broad front of the electorate.  Most dangerously, he lost a combined total of 36 points in the 18-29 demographic.  He still leads by 11 points, but young voters had been the second-most loyal base of his energy — a dangerous base under any circumstances, and one proving to be just that in 2008.  McCain pulled within five points of Obama among women, and now leads Obama among Catholics by 15 points after having trailed by 11 earlier.

Zogby also says that Obama lost ground in the Latino and African-American community.  Maybe McCain’s appearances at the NAACP and the Urban League had an impact.  McClatchy doesn’t give the numbers, and I’d suspect that the movement was small, but that’s still significant.  If Obama loses much ground in either or both demographic, he’s toast.

What happened?  Zogby blames it on the European Tour.  While Obama got adulant coverage from the American media, McCain punctured holes in his self-inflated balloon, and it has had an effect.  He has made Obama look inexperienced and unready, and against all odds, voters actually paid attention.

This, of course, is August, and the general election is a long way off.  However, these trends look very troubling not just for Obama but for the entire Democratic Party.  It looks like both have run out of gas in this electoral cycle, and that may not just be a metaphor.  If the Democrats and Obama offer nothing but populist platitudes and obstructionism on developing American oil production — and American jobs — this summer swoon may only get worse in November.