Even some Obama advisers see a real problem. "Ultimately, all that matters is how the nominee stacks up against John McCain," said one adviser
"Right now, Barack is not connecting with the children of the Reagan Democrats. That's a real concern."

Obama rejects the charge that he has failed to reach important segments of the party, noting that he has shown he can crack Clinton's coalition of working-class voters, women and Latinos with his wins in the bellwether state of Missouri, the swing state of Virginia and the Rust Belt redoubt of Wisconsin. He also showed that he can expand the battleground into the coveted Mountain West, with his convincing win in Colorado.

"I don't buy into this demographic argument," Obama said. "Missouri, Wisconsin, Virginia -- in many of these states we've won the white vote and the blue-collar vote.

"A lot of the states he's winning are states that we're not going to win in November. It's not a strategy that bodes well",said a Clinton supporter.

The original article is too long to clip. It's a worthwhile read.

If Clinton enters the summer on a roll, especially in the big states, the superdelegates may no longer feel that backing her would be opposing the will of the voters, an Obama supporter said.

"Superdelegates are politicians. They will not buck the will of the voters," said a superdelegate supporting Obama. "The danger point comes if the superdelegates don't see a vote for Clinton as bucking anyone."