There are over 330 million people living in the United States, according to the 2020 U.S. Census. When it comes to Congress, those millions live in 435 congressional districts that are represented in Washington D.C. by their own representatives.
The task for drawing those districts was traditionally the purview of state legislatures. Forty states rely on their legislatures to redraw districts, and 35 states rely on them to redistrict themselves, according to the National Conference of State Legislatures.
When state legislators redraw their own districts, it's done by duly elected representatives. Some argue these representatives are best qualified to decide on these boundaries, but others argue this needlessly opens the door for an already powerful majority party to maximize the effect of its supporters while minimizing the effects on the minority voters, ultimately paving the way for less competitive districts.
Iowa does things a little differently. The state stands out among peers for using a nonpartisan process to determine its district lines, but that didn’t happen overnight.
LISTEN: What you need to know about Iowa's redistricting process
How did we get the “Iowa Model?”
Between 1907 and 1964, the Iowa Legislature’s House Districts remained the same. Each state legislative district covered a county, despite some counties having a much larger number of people living in it. Iowa — like much of the country — did not apportion its representation in the state legislature or Congress based on population.
But the U.S. Supreme Court put an end to that. In 1962, it ruled it would reject any district plans brought to the court that did not apportion representation based on population.
While every state gets two U.S. Senators, a state gets a number of representatives in the U.S. House based on the number of people living in that state. The 1962 ruling meant that states, which determine how congressional districts were drawn, must make sure those districts are drawn with a population in each district that is equal “as nearly as practicable” to each other district.
In 1968, the Iowa Legislature amended the Constitution to bring it in compliance with this ruling. They also set a timeline saying congressional district maps, as well as state legislature maps, would occur following the federal census every 10 years.
For the two decades following 1962, the Iowa Legislature redistricted the Iowa House four times and the Senate five times. But that volatility came to an end with a new process that took over in 1980s.
What is the “Iowa Model?”
Rather than the jockeying interests of incumbent legislators, the new process started in the office of bureaucrats.
The Iowa Legislative Service Bureau, which drafted bills for the Legislature, was charged with drawing proposed congressional and legislative maps that would then go to the legislature and finally the governor for approval. While the Bureau was later consolidated into the Legislative Services Agency, it remains the originator of redistricting maps.
The goal of the “Iowa Model” is to get a map that a majority can agree on after offering three chances to get it right. If the Legislature or governor does not like the first map, it’s back to the drawing board for map two. If map two doesn’t satisfy, it's back to the drawing board for a third. But unlike the first two maps, the Legislature can amend the LSA’s third map the same as it would any other bill.
Since enactment in 1980, Iowa has agreed to an unamended LSA map for the last four decades. In 1991 and 2011, the legislature went with the first maps presented. In 2001, it chose the second map. Only in 1981 did it make it to the third map, and even then they agreed to the map without amendment.
Correction: An earlier version of this article included an incorrect figure for the U.S. population in 2020.
