25 September 2012 Last updated at 19:16 ET

Article written by Mark Mardell North America editor

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Romney must work hard to win Ohio

 

Mitt Romney is trailing Barack Obama in a recently released Ohio opinion poll

Republican presidential nominee Mitt Romney's supporters, waiting in the drizzle at the airport in Dayton, Ohio, for the man they want to be America's next president, could make all the difference in this election.

Under the sign "We need a real recovery", four people clutch four big red letters. O-H-I-O. Some think this state will spell defeat or victory for Mr Romney.

He has to work hard - an opinion poll out today puts Mr Obama eight points ahead. It is one of eight key battleground states, and perhaps the most important.

A local reporter tells me that while there are other routes to victory for Mr Obama, Mr Romney cannot afford to lose this state. It is the conventional wisdom.

Political supporters put up with a lot to be a backdrop for a few brief shots on TV. They have been corralled here for hours.

In their plastic rain macs they try to keep their spirits up. One speaker tries a sing along "We love Mitt Romney". It fades after four goes not, I think, from any lack of enthusiasm for the candidate, more because the song itself is rather lame.

A woman has a little better luck spontaneously getting the crowd going, by shouting "Mitt!" and calling for the response "Romney!"

Eventually, the man himself makes a fairly dramatic arrival as his plane slides into view just yards from the stage.

Ground game

Dressed in a red windcheater, he arrives with Republican vice-presidential nominee Paul Ryan, who is still the much better speaker.

Mr Romney ran through a campaign speech that has evolved a fair bit since I last saw him in the flesh.

Grassroots participation could be crucial to a Romney victory in Ohio

There was a great deal more about China, from currency manipulation to intellectual property theft, a fair amount on the Middle East unrest, as well as more general comments on the economy.

But the surprise for many was when he said President Barack Obama had not put taxes up - that was a plan for the second term.

Some are going to make a lot of this, and it does go against the conventional Republican case, but no-one in the crowd noticed the gaffe, if that is what it was.

However, the Romney campaign quickly put out a statement saying that President Obama has put taxes up and Mr Romney was "clearly communicating" that he plans to put them up some more.

Some think that in this state it is all over. One article explains what it calls "Obama's stunning Ohio turnaround".

It is a commonplace that the candidate is not adored by Republicans, but this crowd seemed pretty enthusiastic to me.

They have to work hard over the next few weeks on what is known as the ground game. Big speeches by political superstars matter, and so does costly TV advertising.

But the people leaving the rally clutching Romney signs to put up in their gardens had heard advice on how to win this thing - talk to neighbours, make sure they vote, apply for a postal vote (it makes it easier to check up people have voted), think of something novel - one speaker said she had found a note on a petrol (gas) pump that morning noting how much the price had gone up since President Obama had come into office.

If it is all over, no-one has told the supporters here.