Reply #66: Indeed she can. Obama loses far more Democrats if she's not the nominee:

[Yossariant]

"The vast majority of Democratic voters say they would support either Obama or Clinton over McCain. But in an Obama-McCain matchup, 14% of Democratic voters say they would support McCain, compared with 8% who would do so if Clinton is the nominee...

In addition, female Democrats look at the race differently depending on the matchup. While 93% of women in the party say they would vote for Clinton over McCain, just 79% say they would support Obama over McCain...

A quarter of Democrats (25%) who back Clinton for the nomination say they would favor McCain in a general election test against Obama. The "defection" rate among Obama's supporters if Clinton wins the nomination is far lower; just 10% say they would vote for McCain in November, while 86% say they would back Clinton..."

http://people-press.org/reports/display.php3?PageID=1254