The American presidential campaign, having given Iowa its prolonged season in the spotlight, moved east to New Hampshire and other states with primary elections. But it will be back to the Midwest soon enough—this time to stay. The 2012 election will be decided in the Midwest. Iowa and its neighbours haven’t seen anything yet.

The reason is that the eight states of the upper Midwest—Iowa, Minnesota, Wisconsin, Illinois, Indiana, Ohio, Michigan and Missouri—are mostly swing states. That is, they are traditionally evenly split between Democrats and Republicans. Unlike New England (solidly Democratic) or the South and mountain states (rock-ribbed Republican), these Midwestern states swing back and forth. In a close race, they deliver the verdict.

President Obama carried all eight states in 2008. In the 2010 congressional election, all swung to the right. In 2012, only Indiana, usually Republican, seems safe for either party. The other seven are up for grabs. The old political saw says ‘all politics is local’. In some Midwestern states such as Wisconsin and Ohio, local issues—mostly involving Republican attempts to weaken labour unions—could easily tip the presidential race. We’ll return to these issues in a moment.

But first, a word on the Iowa caucuses, the baffling scrums which kick off the American political season and, as the first vote anywhere, give Iowa its outsized impact on the presidential race. As the world knows, Mitt Romney and Rick Santorum ended in a dead heat, followed by Ron Paul. Other candidates like Newt Gingrich and Rick Perry, trailed far behind.

The thing to remember about the Iowa caucuses is that they are both meaningless and important. First, the meaninglessness. The caucuses were not a normal election. Rather, they were kaffeeklatches in living rooms or libraries, with neighbours coming into the cold Iowa night to vote for their favourite Republican. It’s supposed to produce pure Jeffersonian democracy. In fact, most caucus-goers are party activists, not average voters. The total turnout was only 122,000, or 4 per cent of all Iowans, about the size of your average lunatic fringe.

The Iowa Republican Party is dominated by the far right—mostly in the rural west where the Farm Bureau and evangelical churches hold sway. These are the people who go to caucuses, which is why the candidates had to pander to them, giving outsiders the impression that all Iowans are gospel-walloping bumpkins for whom Biblical inerrancy is a more important presidential quality than knowledge of foreign policy. But if Republicans represent only half the voters in swing-state Iowa, about one-third of these Republicans are evangelicals. In other words, the caucus candidates spent the campaign cozying up to about 15 per cent of all Iowans.

Easterners complain that Iowa is not representative of the nation. In fact, as a well-educated, mostly industrial and urban state, it’s probably as representative as any other. But the Republican caucuses are not only not representative of Iowans, they’re not even representative of Iowa Republicans. This makes Iowa’s caucuses an imperfect barometer of American politics. Four years ago, Mike Huckabee won the Republican caucus: he’s now a right-wing talk show host. But the Democratic caucus that year went to Barack Obama, whose come-from-behind victory in a mostly white state like Iowa was an enormous boost to his campaign.

Iowa caucuses do have their use. By shining an unforgiving light on the candidates through months of campaigning, they weed out the weakest ones. Michele Bachmann, Rick Perry and Newt Gingrich all had their moments. All were revealed as shallow, uninformed and/or unstable, and sank. If Iowa has killed their candidacies, it has done its job. It also has shown how far some centrist candidates, especially Romney, will tilt to the right to win Iowa votes. Some of his Iowa stands—on immigration and the economy, for instance—will haunt him if he gets the Republican nomination.

At the same time, however, labour battles in Ohio and Wisconsin may force the Obama ticket to be more pro-union than it would like. Scott Walker, the Republican Governor of Wisconsin, rammed bills through his Republican legislature that largely ended collective bargaining rights for public service union members, like teachers. Wisconsin has laws permitting voter recall of officials. Already, angry pro-union voters have forced the recall of two Republican state senators. Now, anti-Walker activists seem certain to get the 540,000 signatures required to force Walker, after only one year in office, to face a recall election. This recall election could happen as soon as March. More likely, it will happen in November, on the general election day. Emotions, both for and against Walker, will run high, with an inevitable impact on the entire ballot, including the presidential one.

In Ohio, another Republican governor, John Kasich, also pushed a harsh anti-collective bargaining law through his Republican-dominated legislature. In a referendum late last year, voters repealed that law by a 60-per-cent margin. Ohio has no recall law. But Democrats and unions think they can seize control of the lower house of the legislature. If they get out enough voters to do it, the same voters probably will give Ohio to Obama. Considering that no president in half a century has won office without winning Ohio, this is a prize worth having.

Republicans in Indiana are pushing similar anti-union legislation. Indiana, as noted, appears safely Republican. But who knows? Throw in the stalled national economy, add the controversy over growing inequality, and mix it with vanishing Midwestern industry. Stir together over the fires of traditional Midwestern populism, and this region could come to the boil, just in time for election day.