PIERRE, S.D. (AP) — Supporters of a constitutional amendment that would take control of redistricting from South Dakota legislators and give it to an independent commission hope to put the amendment before voters in 2018, a key supporter said Thursday.

Attorney General Marty Jackley this week filed an explanation of the amendment with the secretary of state's office, a step required before petition gatherers can spread out across the state. Supporter Rick Weiland, a former Democratic U.S. Senate candidate, said the plan — a reprise from 2016 — would make elections fairer in South Dakota.

"Why would we allow elected politicians, why would we afford them the opportunity to draw their legislative district?" Weiland said. "It just doesn't make any sense. When you have complete one-party domination, you're going to get one-party dominated redistricting efforts."

Redistricting is the process of redrawing electoral district boundaries every 10 years to account for population changes. When the process is carried out by elected officials, it often sparks lawsuits and claims of gerrymandering — attempting to draw the districts for political advantage.

Republicans control every statewide office and hold supermajorities in the state Legislature.

The amendment calls for switching control of the legislative redistricting process from legislators to an independent commission of nine people, with no more than three from any one political party. It mirrors a constitutional amendment that South Dakota voters rejected last year.

Political considerations get no mention in redistricting guidance provided by the state constitution. It just says each legislative district must consist of "compact, contiguous territory and shall have population as nearly equal as is practicable." The amendment specifies that party registration and voting history must be excluded from redistricting and that the home of any incumbent or candidate can't be identified or considered.

Under the plan, the commission would redistrict in 2021 and every decade after.

Supporters would have to submit nearly 28,000 valid signatures to the secretary of state by November 2017 for the new amendment to appear on the 2018 ballot. Passage of the amendment requires a simple majority.

The South Dakota Republican Party opposed the unsuccessful 2016 amendment. GOP Sen. Jim Bolin said the measure would give away power to non-elected officials to decide on something the Legislature did well in 2011.

"It's the most bogus, unnecessary thing that is out there," Bolin said. "It was defeated decisively last time, and I hope it's defeated decisively this time."

Redistricting will not affect federal races in South Dakota because the entire state is one congressional district.