Indiana, even its fiercest defenders would acknowledge, is one of America’s less momentous states. Its capital, Indianapolis, is known principally for the car race that takes place against the backdrop of the nondescript city. It has a famous Roman Catholic university, Notre Dame (pronounced to rhyme with “motor lame”), home to a football team that plays in a vast stadium in front of a statue of Christ — inevitably nicknamed “Touchdown Jesus”.

In its 190-year history as America’s 19th state it has produced only one president: the rather undistinguished Benjamin Harrison, elected to just one term of joyless mediocrity in 1888.

But Indiana, your time has come. For the next two weeks the state will be the centre of the political universe. On May 6 it will host the next round in the struggle between Barack Obama and Hillary Clinton for the Democratic nomination.

Although North Carolina also votes that day, Indiana is — the mind slightly rebels at the very thought — The Big One. Mr Obama should win comfortably in North Carolina, but in Indiana the contest seems genuinely wide open.

If Mr Obama can steady his nervous ship and win there, he is probably just about guaranteed the nomination. If Mrs Clinton wins, the race will go on at least to the end of the primary season in June.

The people of Indiana have the voters of Pennsylvania to thank for all the attention they are will get in the next two weeks. On Tuesday Pennsylvania handed a sizeable victory to Mrs Clinton, giving the New York senator one more encore in a campaign that has had more comebacks than Frank Sinatra.

Mrs Clinton won by just enough votes to keep the show on the road. She was expected to win, but her ten percentage-point margin was somewhat better than expected.

For Mrs Clinton the victory was crucial in helping her to make her case to the super-delegates who will decide this nomination battle. Barring a collapse between now and June, Mr Obama cannot be beaten in the race for elected delegates, but he cannot win enough of them to secure the majority a candidate needs to secure the nomination. So the tussle comes down to persuading the super-delegates, the party’s panjandrums and senior elected officials.

Mrs Clinton’s efforts have been directed for some time at persuading these delegates not to simply ratify the votes of the elected delegates but to exercise their own judgment. Her case was strengthened in two ways by the Pennsylvania result.

First, she can argue that Mr Obama is steadily demonstrating what the Clintons believe to be the essential truth about him — that he cannot beat the Republican, John McCain, in November. Mr Obama’s performance among white working-class swing voters in Pennsylvania (as in Ohio two months ago) was simply not good enough to carry the Democrats to victory in November.

The more voters are seeing of Mr Obama the less they seem sure that he should be the next president. His troubles of the past few weeks — especially his careless but revealing contention that working class voters “cling” in their “bitterness” to religion and guns — suggest an arrogant, condescending elitist from an Ivy League university who wouldn’t know an ordinary American if he met one.

The second point Mrs Clinton can make concerns the popular vote. Although it holds no official role in the election decision, the popular vote holds great moral authority. A number of super-delegates could well be persuaded to back the candidate who ends the primary season with more actual votes cast in all the primaries and caucuses.

Before Pennsylvania Mrs Clinton trailed Mr Obama in that tally by 700,000 votes. She has closed that gap by more than 200,000, and if the void results from Florida were counted, the deficit would be down to 200,000.

There are nine states to come and it is just possible that Mrs Clinton could draw level with Mr Obama in the popular vote. If that happened, it would give her a powerful argument that she should be the nominee. It’s a long shot. But the next two weeks will be pivotal and Indiana has a rare opportunity to change the course of history.

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