Every four years, Iowa raises its head to occupy the minds of seasoned analysts, roving reporters and political gurus as the US Midwest state has a strong power over future presidential election campaigns. 

What happens here can boost support for candidates by projecting them into the international spotlight or, more devastatingly for politicians, kill their campaign.

Background

At the beginning of the election year, political parties begin the process of choosing their candidate for president through primaries and caucuses.

How the system works.

Voters in Iowa are the first to have their say on who they want to head into November's poll. 

These results are the first glimpse into how voters are thinking which could make or break a candidate.

How come Iowa goes first?

Wanting to engage more grassroots party members when choosing a presidential candidate, the Democratic Party established a commission to draw up a set of reforms in the late 1960s.

The party aimed to get more members involved rather than giving all the power to party elites when picking a candidate.

But nothing stated that Iowa had to go first.

Democrat officials in the state started to brainstorm about how they would collect party opinion as the new system began. It was all down to timing. 


US election heats up in freezing Iowa


They calculated that the process would need to begin in early spring due to how long it took mimeographs (low-cost duplicating machines) to print information and election forms.

Little did they know that because of their preparedness, this would result in the state going first with their caucus and also with their results.

George McGovern helped shape the modern Iowa caucuses

This schedule continues to operate.

One of the men behind the idea, Richard Bender, told the podcast 'Pod Save America' that it was "a historical accident" that Iowa became number one.

But when did Iowa get so much power?

In 1972 the new format was born and Iowa became the first state to hold its Democratic caucus. The Republican Party adopted the same method four years later.

Another person behind the new nominating order got in the Democrats' race, George McGovern. 

Team McGovern thought they could get some attention in Iowa before heading to the next state, New Hampshire. 

After fixating on the state, McGovern didn't win but did better than anyone expected. 

The foundations were laid for Iowa to become a springboard for campaigns, which was cemented when a soon-to-be president took his focus to the state.

In 1976, Jimmy Carter was vying to be the Democrat nominee for president but had little money or momentum to compete in any of the "big" primaries later in the year. 

Carter put his resources into Iowa in an attempt to prove he could whip up support and build on that traction in New Hampshire.

Jimmy Carter and his wife Rosalynn with Walter Mondale and wife Joan on the last night of the 1976 Democratic National Convention 

His efforts bore fruit and he, unexpectedly, the little-known Southern Governor won Iowa - pushing his campaign further forward with enough power and influence to eventually secure the nomination. 

What happened to Jimmy Carter revolutionised the Iowa caucus and created a long history of surprise candidates for president.

Iowa became a place for grassroots politics to flourish with candidates getting the chance to get up close and personal with voters.

Looking for a victory to leapfrog HilLary Clinton for the Democrats potential nomination, Barack Obama saw that potential once again in Iowa.

With a lagging campaign, Obama at one point trailed Clinton by 26 points and many doubted that the then charismatic Senator's bid for president would continue.

Obama began to channel Jimmy Carter’s efforts. For much of 2007, Obama decamped in Iowa - covering as much ground as possible to keep his campaign alive.

Barack and Michelle Obama campaigning at the Iowa State Fair in 2007

As former US Ambassador to the UN and Obama campaign worker, Samantha Power said in her recent book: "I didn't know whether winning Iowa was feasible, but I did recognise that it was his only viable pathway to the presidency."

The mobilisation paid off and Barack Obama defied the polls after generating immense support and ending up piping the post in Iowa. 

His support was mostly from under-30s who never caucused before.

Barack Obama has said since that winning the Iowa caucus was the highlight of his political career as the state showed the country it was possible for an African-American politician to mass support from a predominantly white state.

Even though Iowa is not a representative insight of the United States, as it is over 90% white, it still to this day remains a strong indicator of how a presidential candidate will do in later contests by sending messages to not only national party leaders but voters too.