Oh boy is the Democratic nomination race about to become complicated. More so than in any such election for more than fifty years. This battle is supposed to be about who accumulates the most delegates, which sounds very simple. In fact, it has become a quest to demonstrate who has won the better quality of delegates in the contest.

It will take about 2,025 delegates to win the nomination. But of the 4,000 odd souls who will have a vote when the Democratic convention assembles in Denver at the end of August, only 3,250 will have been selected through primaries and caucuses. The remaining almost 800 are the so-called “superdelegates” — elected persons such as Senators, members of the House of Representatives and Governors — as well as senior unelected officials such as the leaders of state Democratic parties. The superdelegate system was invented in the early 1980s as a handbrake in case a front-runner emerged who was wildly popular with atypical liberal activists but not the wider party or the American electorate at large.

The results last night mean that it is impossible for either Barack Obama or Hillary Clinton to secure the nomination based on the primaries and caucuses alone. Either one has to seize at least a decent-sized minority of the superdelegates to prevail in this struggle. The remaining 12 state competitions are, therefore, in a sense not really about winning the prize through the delegates obtained in these places but impressing the superdelegates whose principal concern will be the electability of whoever ends up representing the Democrats in November.

The Obama and Clinton camps will put forward two very different views of whose pledged delegates are superior. Even if Senator Clinton beats him in most of the remaining primaries, the fact that delegates are distributed by proportional representation makes it highly likely that Senator Obama will end the nominating season with more pledged delegates than her. He is already contending that this makes him the “moral” victor and it would be obscene if the superdelegates denied him the nomination subsequently.

This is a strong argument, but only up to a point. There is a division that can be identified within the pledged delegates that may be highly relevant to superdelegates. Among those delegates who have been chosen in caucuses (where turnout is often tiny and dominated by ideological individuals), Obama holds a comfortable lead over Clinton. In states which employ the primary method, by contrast, the two are virtually even and assuming she wins the Pennsylvania showdown on April 22 (which is probable) then she will have the lead within this category even if she is behind him overall.

The split between primaries and caucuses was illustrated perfectly in Texas. That state has an odd hybrid system in which two thirds of its delegates are picked on the basis of its primary and the other third in caucuses which took place right after the primary poll had closed. She seems to have won the primary by 51-47 per cent. He looks as if he took the caucus component (where far fewer votes were cast) by 55-45 per cent. Depending on how the final arithmetic develops it is possible that he could emerge from Texas with more delegates than her even though this newspaper, like every other media outlet, is reporting “Clinton wins Texas”. I did warn this was complicated.

This sort of pattern will disturb the superdelegates. They will worry that Senator Obama consistently fails to win the primaries held in large states (the only one in the top ten by population he has taken is in his home state of Illinois). Many of those who supported Senator Clinton in Ohio yesterday, for instance - disproportionately white voters, often women, on modest incomes - may prefer John McCain to Senator Obama come November. If that happens, the Republicans will retain control over the White House.

So the Obama claim that if he wins most of the pledged delegates then the superdelegates should and will follow their lead may prove hollow in practice. Of the remaining 12 states left, nine are holding primaries and just three caucuses (two of which are in little Guam and Wyoming where there are not many voters or delegates to be had either). If Senator Clinton were to emerge behind on overall pledged delegates but ahead on primary delegates then I think she has a better than even chance of being awarded the nomination by virtue of the superdelegates. The Obama fraternity will scream foul even if she attempts to appease him with the vice presidential nomination (which now strikes me as an offer that she has to make if she is victorious). Oh to be in Denver cometh August.

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