It's been said in some quarters that the Democratic party would not be in this "mess" if it didn't use a proportional system of representation in the primaries. In other words, if we were more like Republicans and the winner-take-all mentality, the race would've been over a long time ago with a clear victor.
Reading through the lines with the "big blue primary states only" argument, the suggestion is we would've had Clinton as the nominee.
I can't comment on what effect "momentum" would've had in those circumstances, but I can get out the spreadsheet and do a little experiment with the results we have so far. So, what if each primary or caucus thus far were a winner-take-all affair? Where would the Democratic race stand?
Results (drum roll please...) on the flip.
Using Real Clear Politic's current delegate count, counting only pledged delegates, as of today the race stands at
Obama 1395
Clinton 1237
If we simply award winner-take-all for each contest held thus far, omitting Michigan and Florida, the numbers are:
Obama 1257
Clinton 1430
BUT, this is counting Texas as a Clinton victory. This is tricky; if you count either the caucus instead of the primary (questionable) or add caucus and primary vote totals (somewhat less questionable, but still not quite cricket), and award Texas to Obama, you get
Obama 1450
Clinton 1237
Interestingly, Clinton has exactly the same number of delegates under this scenario as she does in "real life".
In either scenario, the race would be a bit wider than under the current system, but by no means settled in any meaningful sense, particularly if one awards Obama the Texas delegates.
Just for "fun" I also did a total of only states that the Democrats have won in both of the last two Presidential elections:
Obama 632
Clinton 823
Take that for whatever it's worth; I certainly don't know if it's relevant, but that's the argument that's been made by one camp.
UPDATE: the above "blue state" numbers are winner-take all, the hypothetical scenario. I went back through all the actual, proprotional, blue state numbers and the totals there are:
Obama 727
Clinton 677
So, even if you accept the "only blue states count" logic, you'd have to have a winner-take-all-delegate system for there to be a meaningful distinction between the candidates. I suppose this is simply another way of restating the fact that when Obama has lost, he has mostly lost quite narrowly, but when Clinton has lost, she has often lost large.