A few hours before caucus night Randy Riecks will take down his Christmas tree to make some space in his living room, unfold 30 chairs borrowed from the local church and decide which bedroom Hillary Clinton, Barack Obama and John Edwards’s supporters will stand in.

Mr Riecks is a Democratic precinct captain in the tiny hamlet of George, in the remote, far northwest corner of Iowa, just a few miles from the Minnesota border. While nearly all caucus-goers in the state will be in large school gyms and community centres on Thursday night, in George about 30 will congregate a few feet from Mr Reicks’s kitchen table.

Before the Democratic caucus-goers arrive, many with home-made snacks, Mr Riecks will vacuum the house, make coffee and take a final look at the thick packet of instructions sent to him by Iowa’s state Democratic party. His wife Sue — who will probably make chocolate chip cookies — is an independent and has offered to babysit the toddler of one woman due to attend.

George sits in a frozen expanse of farm country, where hog production and cornfields dominate, covered this week by snow. It has a population of 1,500 but because of the extraordinarily outsized influence the Iowa Democratic party gives its rural areas on caucus night the 30-odd people who will sit in Mr Riecks’s living room on Thursday night will get to elect four delegates.

There are precincts with vastly greater populations and attendance that get to elect just a few more. In a close race what happens in living rooms such as Mr Riecks’s could tip the race. John Edwards nearly won the 2004 contest because of support in the sparsely populated rural areas.

At 7pm they will begin to caucus in the living room. Anybody can stand up and talk about a candidate. After a while Mr Riecks will ask those who have settled on a candidate to move to different parts of the house. One group will go to the master bedroom; another to the spare bedroom. A third into the kitchen — and if there is a fourth, into the living room.

If a candidate is not viable — that is, has less than 15 per cent of the total number of caucus-goers in Mr Riecks’s house, the haggling begins to get supporters join other groups.

Mr Riecks unfolds a poster entitled Caucus Mathematics. The key equation reads: [Number of members within the group] X Number of delegates the caucus elects divided by Total Number of eligible caucus attendees = number of delegates to be elected to this group. It continues: “When awarding delegates, decimals of 0.5 and greater are rounded up and decimals less than 0.5 are rounded down.”

That’s caucus democracy in Iowa. Mr Riecks has a calculator.

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