Can Hillary Clinton still win?

The more things change, the more they stay the same.

After a slew of primary and caucus victories for Barack Obama - who has been out-organising Hillary Clinton's machine, and getting months of media adulation - he has been suddenly stopped short of coronation.

Mrs Clinton won in Ohio, Texas and Rhode Island, and once again, the race is on.

Even more importantly, it seems for the first time in a long time that her message of experience and getting things done may outweigh his call for change.

Yet despite Mrs Clinton's burst of momentum, and Obama's success, it is impossible for either one to secure the 2,025 delegates that would give them the Democratic nomination with pledged delegates alone.

Both need the support of many of the 796 super-delegates - the elected officials and party dignitaries who have special voting rights in the nominating process - to get the nomination.

So, despite months of glee over big turnouts and voter enthusiasm, the hand-wringing has begun anew in the Democratic Party over how to get to a nominee.

Obama's upper hand

There are two mathematical realities that matter to both campaigns.

• First, winning delegates does not necessarily mean winning the popular vote. Mrs Clinton's victories in a pile of big states including New York, New Jersey, California, Texas, Ohio and Massachusetts have kept her within striking distance of taking the popular vote from Obama
• Second, no matter how well Mrs Clinton does in the remaining state contests, come June - at the end of the primary and caucus season - Mr Obama will have more pledged delegates than she will

Mr Obama also has a clear upper hand with super-delegates so long as he has the majority of pledged delegates and the majority of the popular vote.

DEMOCRATIC DELEGATE RACE
BARACK OBAMA: 1,578

• Delegates won on 8 March: 7
• States won: 25

• Delegates won on 8 March: 5
• States won: 16

Source: AP at 1000 GMT 10 March

Q&A: Delegates

Q&A: What next?

Harrison Hickman, a prominent Democratic pollster and advisor to John Edwards, has a theory for the reason behind the reluctance among super-delegates to veer away from the candidate with the pledged delegate lead. He calls it "Gore Guilt".

He says that Democratic voters felt so bruised by the 2000 election - in which former Vice-President Al Gore went all the way to the Supreme Court to fight for lost Florida votes that could have made him president - that they are reluctant to allow the nomination to be decided by a cabal of elected officials and party dignitaries voting in accordance with their own personal beliefs.

Yet it is precisely this argument that Mrs Clinton will have in her corner if she can win the popular vote.

POPULAR VOTE

• BARACK OBAMA: 13.6m

• HILLARY CLINTON: 13.3m

Recent polling confirms this. A 6 March Rasmussen poll shows that 57% of Americans think the candidate with the most votes should win the Democratic nomination. Only 26% of Americans think the candidate with the most delegates ought to win.

No room for error

Along those lines, Mrs Clinton's path to the nomination depends on accomplishing three things.

• First, Mrs Clinton must win the popular vote so that she can present her majority as a reason for super-delegates to get behind her
• Second, Mrs Clinton must also lessen the gap between her number of pledged delegates and Mr Obama's. Mr Obama already has one more caucus victory this week: Wyoming, which he won by a large margin on Saturday. He is also favoured in the upcoming contests in Mississippi and North Carolina. Mrs Clinton must win decisively in Pennsylvania, West Virginia, Kentucky, Indiana and Puerto Rico. Florida and Michigan, two states which have been disqualified from the process for breaking with party rules, also hang in the balance
• Finally, Mrs Clinton must prove resoundingly that she is the more electable of the two candidates in a general election and would be a better president. She must combat Mr Obama's claim to the mantle of change and at the same time emphasise her credentials to prove that she is best able to beat John McCain

Super-delegates do not have to vote until the end of August, at the Democratic Convention in Denver.

Six months is plenty of time to build an unbeatable argument for super-delegate support - but there is little room for error and almost no room for losses.

Molly Levinson is a political analyst and former CBS News Political Director

RELATED INTERNET LINKS
Real Clear Politics: Democratic popular vote
The BBC is not responsible for the content of external internet sites