What is it? Most Obama supporters go by the official line of 2,024. (It fluctuates up and down almost daily on DemConWatch) Many Clinton supporters say he'd need 2,208 (the number which would include MI and FL).
I say he needs 2,100 without Michigan and Florida to shut the door on this.
Here's my reasoning. It sounds like Hillary wants to stay in all the way to the Convention if there's any chance at all of her being able to prevail, which would include the chance of battling for all of Michigan and Florida's delegates. According to
DemConWatch, Florida would add 105 for Clinton, 67 for Obama. If Uncommitteds in MI went to Obama, Michigan would add 73 for Clinton, 55 for Obama. Additional superdelegates for the two states: 15 for Clinton, 5 for Obama.
That works out to a total of 193 for Clinton, 127 for Obama, and would increase the total delegates needed from 2,024 to 2,208 because there would be an additional 35 superdelegates in MI and FL who are currently uncommitted to either candidate.
So let's say just for the sake of argument, we assume that Obama needs to ensure he'll have 2,208 including MI and FL. That means without MI and FL, he needs 2,208 - 127 = 2,081. But let's give Hillary the benefit of the doubt on Uncommitteds in MI: Let's say 15% of MI delegates should go to Edwards. That's 15% of 128 = 19 delegates away from Obama's total. So Obama gets only 36 delegates from MI under this scenario.
Add 19 to 2,081 and you get the nice round number of 2,100.
-----
So, if Obama has 2,100 total delegates in early June, including superdelegate endorsements, then adding Florida's 67 delegates, plus 36 delegates from Michigan, plus 5 additional superdelegates who have endorsed, would give him 2,208. It would truly be a mathematical impossibility for Clinton to win without some superdelegates changing their votes. It would probably seal the deal.
-----
Now let's look at what it would take for Obama to reach 2,100 in early June.
-----
Here's one scenario.
State | O Del. - C Del. | O % - C %
PA ... | .. 71 ..... 80 .. | 47 .... 53
IN ... | .. 38 ..... 28 .. | 58 .... 42
NC ... | .. 51 ..... 40 .. | 56 .... 44
WV .. | .. 11 ..... 15 .. | 42 .... 58
KY ... | .. 22 ..... 25 .. | 47 .... 53
OR ... | .. 25 ..... 23 .. | 52 .... 48
PR ... | .. 25 ..... 26 .. | 49 .... 51
MT ... | ... 8 ...... 7 .. | 54 .... 46
SD ... | .... 8 ...... 6 .. | 56 .... 44
GU ... | .... 2 ...... 1 .. | 53 .... 47
ALL .. | .. 261 ... 251 . | 51 .... 49
Add 261 to Obama's current total of 1616 and you get 1,877.
At this point Obama would still be leading in Pledged delegates, Number of states, and Popular vote (I calculate that this would be true even including MI and FL, if the above percentages came true).
In order for Obama to get to the magic number of 2,100, then, he would need another 223 Superdelegate endorsements - occurring either by flipping some of Clinton's current supers or by currently uncommitted supers endorsing him.
If we were to assume that all of Clinton's superdelegates stayed with her, Obama would need 66.2% of the 337 remaining uncommitted superdelegates to endorse him in early June after all primaries were over.
IMO if he has won every category, this could easily occur. Once he passes the 2,024 mark (with perhaps another 150 supers), the others would come flooding in and he would easily reach or exceed 2,100.
At this point there would be no argument left for Hillary to take the fight to the Convention.