Hillary Clinton didn't exactly become the Comeback Kid again with her primary wins on Tuesday. But her victories in the popular vote in Texas and Ohio were enough to make her at least, for now, the Campaign They Couldn't Kill.

Senator Clinton's own husband had said that she needed to win the two states to stay in the Democratic race. In the past few weeks, as Barack Obama notched up victory after victory, that bar seemed to be getting higher. But on Tuesday she cleared it.

In the process she ensured she stays in the race at least until the next big contest in Pennsylvania on April 22. That gives Mr Obama more chances to stumble as he did in the final stages of the Texas and Ohio races.

And while her victory did not come close to eliminating the solid advantage Mr Obama enjoys among delegates — the people who will actually choose the Democrats' presidential nominee at their convention in August — it provided her with the narrowest of openings to make the case, in what will essentially now be more of an argument than an election, that she should be candidate.

A race like a crackpot Dynasty

The contest between Barack Obama and Hillary Clinton matches any fiction

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BACKGROUND

• The ascent of Barack Obama, Mr Charisma

• Decay, jobs and guns fall under the spotlight

• Free trade: Clinton/Obama's mistakes

Because Democrats allocate most of their delegates proportionate to the votes cast in each state, Mrs Clinton narrowed the gap only a little on Tuesday. She still trails Mr Obama in pledged delegates — those who are chosen directly in relation to the primary votes cast — by more than 130, about 1350 to 1220. But the remaining contest will be largely about persuading the so-called super-delegates, the senior party officials who get ex officio votes at the convention, and who make up almost 20 per cent of the total, how they should vote.

It has been clear for some time that neither candidate will win enough of the pledged voters to win a clear majority of the 4000 or so delegates needed to secure the nomination. There are only about 700 of these to be had from the remaining primary contests. So it will be the super-delegates who will tip the balance. The question is: how should these 794 keepers of the Democratic party flame make their decision?

Both candidates are striving to establish an unassailable legitimacy so that the super-delegates will feel obliged to vote their way.

Mr Obama has maintained all along that they should vote for the candidate who wins most of the pledged delegates, since only they will have been directly elected by the voters. This, not surprisingly, almost certainly means he would be the nominee because there simply are not enough pledged delegates left in the remaining races for Mrs Clinton to overhaul his total.

Mrs Clinton's campaign figure it differently. And they could have an equally plausible claim on legitimacy — the popular vote.

In all the 42 contests that have been held so far Mr Obama has outpolled Mrs Clinton in the popular vote by about 51-49 per cent.

Even if she wins a clear majority of the remaining 12 states it is unlikely she can close that gap. But there is still a way she can draw level with him.

Two big states, Michigan and Florida, have in effect had their primary votes nullified because they broke party rules by holding their elections early. For some time, Mrs Clinton's campaign has been arguing that the party should rewrite its rules and allow those delegates to vote. Needless to say she won both by handsome margins.

Even if the party refuses to overrule its own procedures, she could make an argument based on legitimacy by saying the super-delegates should take into account the popular vote — at least in one of those controversial states.

In Michigan Mr Obama's name was not even on the ballot so she can hardly claim that the contest was a serious one. But he was on the ballot in Florida. Though neither candidate campaigned there, Mrs Clinton won comfortably.

If you add Florida's vote totals to the overall popular vote the gap between the two drops to 50.5 per cent to 49.5 per cent, a difference of just 288,000 votes out of 27 million cast. If she can win a majority of the remaining primaries Mrs Clinton could just about close that completely.

In essence that means the Democratic race would end in something close to a statistical dead heat. And then the party elders are going to have to decide how to settle it.

Who would have thought it? Eight years after the most controversial presidential election in modern American history, the identity of the next president could hinge on arguments about the legitimacy of the popular vote and the disenfranchisement of voters in Florida.

Only this time there will be no Supreme Court to decide it. Just a very ugly political brawl.

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