Why does she continue to run?  Because he lets her. 

Poor henpecked Obama has been surrounded by demanding women his whole life and is used to being deferential to them, if not capitulatory.  His wife Michelle, for example, seems to wear the pants in their household.  Like a wolf, HRC sniffed out this weakness toward women in Obama.  Remember the hue and cry over his gentlemanly defense of her being "likable enough" during an early debate?  Women voters, no doubt stoked by Hillary, smacked him down as being arrogant.  That he took it without a fight was a twofer for her:  portraying him as uppity for his old fashion chivalry while simultaneously emasculating him for not fighting back.  If HRC were a white man and Obama treated "him" with that much deference, no one would vote for him, least of all black Americans.  My suggestions for Senator Obama:

Listen to Michelle on this one.  It's okay to hate Hillary Clinton.  Most Americans do.
 
Put her away for good.  She's not dead in the water because she's not dead.  In fact, she's the Undead, bleedin' you of all self respect.  Drive a stake through her heart and wrap garlic around her coffin.

Once she's dead politically, don't resurrect her as your Veep.  Remember Vince Foster?

With the nomination in hand move rapidly to the center politically.  You must move fast because you have a long way to go from deep left field.  Shed the metrosexual look and attitude as you go.  Middle America expects you to be a man, not a hermaphrodite.   

In the general election treat John McCain with collegial respect, not deference.  He's not a girl and won't pretend to be offended.

If you win, do something dramatic your first week in office as President.  Possibilities include repealing Title IX, declaring a National Take Your Son to Work Day, or relocating the Department of Education to the Pentagon.  The crisis affecting boys in K - 12 schools is a national security concern.

I know you have two daughters (as do I).  Adopt a couple of boys.  That'll keep Michelle busy for your first term.

As President, be a role model for all young boys, black and white.  They sorely need one.