At the beginning of an election year, national news anchors and political journalists start talking about Iowa quite a bit more than they usually do. That’s because Iowa holds the very first caucus of the presidential nomination process, and it’s considered an important early predictor of each candidate’s chances of winning the presidential nomination at their political party’s respective national convention later in the year.

Maybe you assumed Iowa gets to vote first because it’s largely composed of middle-class citizens, or simply because it’s in the middle of the country. In fact, neither are true. Iowa clinched the earliest time slot in the schedule mainly because its caucus was a lengthier process than those of other states.

Back in 1968, the U.S. was tensely divided over several major issues such as civil rights and the Vietnam War. Following the assassinations of both Martin Luther King, Jr. and presidential candidate Robert Kennedy in the spring of 1968, protestors descended on Chicago that August for the Democratic National Convention, which was marred by riots and other acts of violence. At the same time, the nation watched anxiously to see who would emerge victorious as the Democratic nominee for president. It turned out to be Hubert Humphrey, Lyndon B. Johnson’s former vice president and a candidate who hadn’t won any primaries at all.

According to History.com, many voters interpreted this as a problematic gap between public opinion and the actions of party leaders, and the McGovern-Fraser Commission was established to try to close that divide. The commission instituted a rule that required state party leaders give the public a minimum 30-day advance notice before any primaries or caucuses to encourage and increase voter turnout. As NPR reports, it also spread the schedule out in each state. Iowa’s process happened to be an especially long one—with a state convention preceded by precinct caucuses, county conventions, and district conventions—so, beginning in 1972, the Democratic Party had Iowa vote first, and the GOP did the same in 1976.

Leading up to the 1976 Iowa caucus, Jimmy Carter was a relatively unknown former governor of Georgia with a pretty low profile and even lower funds. He finished in second place during that caucus, behind Iowa’s “uncommitted” group of voters, and many people considered his later presidential victory a result of his strong performance in Iowa.

The Midwestern state has remained first on the caucus schedule ever since, and although it's not always an Iowa pick who ends up in the Oval Office, the Iowa caucus has become viewed as a key part of the nomination process.

"The really important thing to remember about Iowa is not that it's first because it's important," Kathie Obradovich, former political columnist for the Des Moines Register, told NPR. "Iowa is important because it's first."