HALPERIN'S TAKE: Painful Things Hillary Clinton Knows — Or Should Know

1. She can't win the nomination without overturning the will of the elected delegates, which will alienate many Democrats.

2. She can't win the nomination without a bloody convention battle -- after which, even if she won, history and many Democrats would cast her as a villain.

3. Catching up in the popular vote is not out of the question — but without re-votes in Florida and Michigan it will be almost as impossible as catching up in elected delegates.

4. Nancy Pelosi and other leading members of Congress don't think she can win and want her to give up. Same with superdelegate-to-the-stars Donna Brazile.

5. Obama's skilled, close-knit staff can do things like silently kill re-votes in Florida and Michigan and not pay a political price.

6. Many of her supporters — and even some of her staffers — would be relieved (and even delighted) if she quit the race; none of his supporters or staff feel that way. Some think she just might throw in the towel in June if it appears efforts to fight on would hurt Obama's general election chances.

7. The Rev. Wright story notwithstanding, the media still wants Obama to be the nominee — and that has an impact every day.

8. Obama might not be able to talk that well about the new global economy, but she (and McCain) can't either.

9. Many of the remaining prominent superdelegates want to be for Obama and she (and Harold Ickes) are just barely keeping them from making public commitments to him.

10. She can't publicly say more than 2% of all the things she would like to say about race, electability, beating McCain and experience.

11. If she somehow found a way to win the nomination, she would have to offer Obama the veep slot, and she doesn't want to do that.

12. This is a change election, and Bush-Clinton-Bush-Clinton can never truly be change.

13. Obama is having fun most days, and she isn't.

14. Even though her campaign staff is having more fun than it has for a long time, there's hardly anyone there who, given half a chance, wouldn't slit Mark Penn's throat -- and such internal dissension won't help her in the home stretch.