Rupert Cornwell: This could go all the way to a floor-fight at the convention

Could the razor's edge contest between Hillary Clinton and Barack Obama hinge on the two "primaries that never were" – last month's contests in delegate-rich Michigan and Florida that the Democratic National Committee refused to sanction?

The dispute began when both states violated an agreement that apart from Iowa, New Hampshire, Nevada and South Carolina, no state could vote before Super Tuesday. Determined to boost their say in the process, Michigan and Florida defied the party leadership and moved their primaries forward, to 15 and 29 January respectively.

The Democratic National Committee (DNC) hit back by decreeing that the results would not count and the delegates at stake – 210 for Florida and 156 for Michigan – would not be seated at the nominating convention to be held in Denver, Colorado, in August.

In almost any other year, the row would have been merely an arcane footnote to history, but without bearing on events in the real world. So tight is the race, however, between senators Obama and Clinton that these 366 delegates could be pivotal if the party assembles in Denver with neither candidate having lined up the 2,025 delegates needed to ensure victory, even with help of the 796 "super-delegates", appointed outside the primary and caucus system.

If so, then Mrs Clinton looks in the stronger position. In Michigan she won by default, after both Mr Obama and John Edwards took their names off the ballot, in deference to the DNC. In Florida, all three were on the ballot, but did not campaign. Even so, an unprecedented number of Democratic voters turned out anyway, eclipsing the previous record of 1.3 million in 1988 – and she trounced Mr Obama by 50 per cent to 33 per cent before flying to the state for an unscheduled victory rally.

Not surprisingly, Mrs Clinton vows to fight to have delegates from both states seated in Denver. If she enters the convention with the largest number of valid delegates, then she could expect to force, and win, a floor vote allowing that to happen. If Mr Obama has more delegates, he might succeed in disbarring two states won by his opponent – but at the cost of appearing an anti-democratic spoilsport.

In any case, it would be the first such showdown since 1976, the last time a major party went into a convention without knowing its nominee in advance. That year Gerald Ford, the incumbent president, narrowly led the challenger Ronald Reagan, but without an overall majority of delegates. In the event, Mr Ford prevailed, first winning a crucial technical vote about the announcement of a vice-presidential running mate and then the nomination itself, by 1,187 delegate votes to 1,070.

In 1984, the same thing nearly happened with the Democrats after Gary Hart – the upstart Colorado senator who had something of the freshness of Mr Obama now – had nipped at the heels of the front-runner Walter Mondale throughout the primary season.

At one point it seemed that Mr Mondale, establishment candidate then as Hillary Clinton is now, might actually lose the nomination. But he managed to pull strings to secure enough uncommitted delegates to go into that year's convention in San Francisco certain of victory.

Since then both parties have invariably settled on a candidate early in the primary season. In 1992, Bill Clinton wrapped up the nomination by the end of March. In 2000, Super Tuesday settled matters for both parties, and in 2004, John Kerry became the nominee presumptive by late February.

But 2008 is different. If the deadlock lasts until Denver, it will be hard to resist Florida's and Michigan's claims. A rejection of Florida makes Democratic strategists shudder. The party, they argue, cannot afford to alienate the local Democratic machine in 2008, when Florida could be crucial to the outcome on 4 November. "Down here we have strong feelings about having our votes not count," one local activist said yesterday, in a pointed reference to the hanging chads, butterfly ballots and the rest which probably cost Al Gore the White House eight years ago.

The remaining battlegrounds

Democrats

9 February

Louisiana Delegates: 67

Nebraska 31

Washington 97

10 February

Maine 34

12 February

District of Columbia 37

Maryland 99

Virginia 101

19 February

Wisconsin 92

4 March

Texas 228

Ohio 161

Rhode Island 32

Vermont 23

Republicans

9 February

Kansas 39

Louisiana 47

Washington 40

12 February

Maryland 37

Virginia 63

District of Columbia 19

19 February

Wisconsin 40

4 March

Texas 140

Ohio 88

Rhode Island 20

Vermont 17

* delegate totals include those awarded on the day plus super-delegates who do not have to choose to commit until the conventions