MINNEAPOLIS — Excitement over wide-open Republican and Democratic presidential primaries brought 320,000 Minnesotans, or about 8% of eligible voters, out to pick presidential candidates on a cold March night in 2016.

Such a showing would be abysmally low for a presidential election in Minnesota, when voter turnout routinely tops 70%. But it's a really big showing for a caucus. So big that it overwhelmed some of the state's precinct locations with hour-long lines, and, in some cases, not enough ballots.

Two months later, then-Gov. Mark Dayton signed a bipartisan bill that changed the way the state chooses who its presidential delegates go to, switching from the party-run caucus system to a state-administered primary election. (Party caucuses aren't going anywhere — they're just not how Minnesota chooses presidential candidates anymore.)

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The nonprofit news outlet MinnPost provided this article to The Associated Press through a collaboration with Institute for Nonprofit News.

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Minnesota's not alone. States are increasingly souring on the caucus system as a means of awarding presidential delegates to pick a party nominee.

Experts say the switch could change not only who participates in presidential selections, but also the way candidates campaign and maybe even which candidates are chosen.

Minnesotans have registered their presidential preferences in precinct caucuses for most of the last century.

As opposed to a primary, where voters go to their polling place and cast a ballot, caucuses are like big neighborhood meetings. In addition to picking candidates, caucuses are held to discuss party business. They start at a given time — usually 7 p.m. on a Tuesday, and end an hour or two later.

Fans of caucuses say the discussion component makes them a higher quality system, said Costas Panagopoulos, a professor of political science at Northeastern University who studies voting behavior. "The deliberative nature of these caucuses, and the more direct interaction with voters and neighborhoods, et cetera, is something that is perceived by many to be an advantage and a much higher-quality process," he said.

Detractors say the fact you have to be there at a specific time to make your preference known limits who shows up.

Caucuses are deeply rooted in American political tradition, beginning as meetings where party elites would decide party business and choose candidates. Over time, the process opened up to a wider swath of participants. Seeking to further open up the process, lots of states started switching to the primary process in the '70s.

Minnesota has flirted with both systems, switching from caucuses to presidential primaries, and then back again, every three to four decades since the nineteen-teens, according to a history of Minnesota primaries by Eric Ostermeier, a research fellow at the Humphrey School of Public Affairs.

Primary turnout is always significantly lower than general election turnout in the same election cycle. But if primary turnout is low, caucus turnout is lower.

Amid the 2016 election, Sabato's Crystal Ball, a political predictions website, found that turnout was more than three times higher in states that had held primaries, as of late April, than in states that had held caucuses.

It's not just that fewer people show up to caucuses. Caucus voters also represent a different part of a party's ideology than the primary electorate. Research shows people who show up to caucus tend to bring with them views that are further to the right or the left, depending on the party, than primary voters or rank and file voters.

"It's much more likely that the more ideologically moderate candidates have a better chance in primaries compared to caucuses, and the views that voters espouse on policy issues tend to be less extreme overall in primary systems," Panagopoulos said.

On the Democratic side in 2008, caucus states favored Barack Obama over Hillary Clinton. In 2016, on average, they favored Bernie Sanders over Hillary Clinton. On the Democratic side, the Upshot found that, accounting for demographic differences, Hillary Clinton had a 20 percentage point disadvantage in caucus states compared to both Obama and Sanders.

In Minnesota, Obama won the majority of the state's delegates, with 66% of caucusgoers' support in 2008. Eight years later, Bernie Sanders won the majority of Minnesota delegates with 62% of cacucusgoers' support.

It's too early to tell exactly what the new primary system means as far as who Minnesotans will support with their presidential delegates in 2020.

With Republican President Donald Trump set to seek a second term, it looks as though the main primary contest will be among Democrats. While the Democratic field is getting crowded, there's still time for more candidates (like Joe Biden) to enter.

Ken Martin, the state DFL chair who supported the switch to a primary, isn't ready to make predictions about what will happen in 2020 in the newly minted primary state. "We don't know what the field looks like, we don't know who's going to win Iowa or who's going to be around by March 3," the date of Minnesota's presidential primary. He is expecting turnout to be high.

Minnesota Republican Party Chair Jennifer Carnahan said she never missed an election as a Republican voter, but it wasn't until she showed up at her precinct caucus in 2016 that she decided to get involved in politics.

There are pros and cons to both primaries and caucuses as methods of choosing a presidential nominee, she said — caucuses might inspire people who show up for the presidential contest to get further involved in party politics like herself, but primaries open up the process to more people.

"The changeover will for certain drive a higher turnout to the primaries, and will probably drive a lower turnout to caucuses," she said.

As for what it will mean for candidate selection in 2024 and beyond, Carnahan said that's too far out to tell.

"The individuals who go to the caucus or have been attending caucuses for many years are what I would call our highly engaged super activists, who are really involved in party politics," she said. Now, "you're generally just going to have a larger quantity of people turning out."

Several states that caucused in the presidential nomination process in 2016, including Minnesota, Colorado and Washington, have switched to primaries for 2020. Just six states are lined up to caucus in the forthcoming presidential contest, including Iowa, the first state to pick candidates.

Will that have a huge effect on who wins the Democratic nomination? Maybe not: Despite Sanders' and Obama's substantial advantages in caucus states, the Upshot found it only translated to a 3 percentage point advantage in delegate count for each.

"If the 2008 election season had been run by the 2020 rules, it is not clear whether Mrs. Clinton could have become the Democratic nominee, even though it was one of the closest nominating contests in history. It would have basically been a tie," the Upshot wrote.

The switch by many states from primary to caucus might just change the way candidates campaign, Martin said.

"In a primary, you have to run a much bigger campaign. Most of it is TV and mail, and it's not focused as much on organizing at the grassroots level. It's much more expensive," Martin said. "Those states that still have caucuses tend to favor those candidates who can organize the grassroots, who can inspire people to come out and commit to that process."

The nonprofit news outlet MinnPost provided this article to The Associated Press through a collaboration with Institute for Nonprofit News.