As resources dwindled, manpower-intensive caucus states were abandoned in favor of delegate-rich primary battlegrounds, a critical error that allowed Obama to amass a pledged delegate lead that Clinton was never able to overcome.

CNN: Analysis: Why Clinton's bid failed

That poll questioned 400 likely Democratic primary voters and has a sampling error of plus or minus 5 percentage points.

CNN: 150 delegates up for grabs Tuesday

So did her reluctance to admit error, as many primary voters urged her to do over her Iraq war vote.

CNN: Analysis: Why Clinton's bid failed