PHOENIX (AP) — Republicans in the Arizona Senate approved a measure Tuesday asking voters to limit the population differences between Arizona's 30 legislative districts.

Democrats said the measure would make it harder to create legislative districts with a majority of Native American voters, which has helped ensure the Navajo Nation has representation in the Legislature.

The measure by Sen. J.D. Mesnard would require the state’s redistricting commission to create districts with a maximum difference of 5,000 people. Currently, a 10% difference is considered constitutional, meaning districts can vary by about 20,000 people.

“It is very very sad that the Native American people, the people of the first nations, the people that have been here since we were placed here by the holy people, would not have a voice in these chambers,” said Rep. Jamescita Peshlakai, a Democrat from the Navajo Nation.

Mesnard argues that his measure, which would require voter approval, is an effort to get as close to a one-person, one-vote threshold as possible. Creating districts with up to a 10% difference can disenfranchise voters, he contends.

“If you're in a district where they essentially overpopulate, where they stack, those folks have less representation,” Mesnard said.

Republican Sen. Kate Brophy McGee joined all Democrats in opposition.