Republicans say that outcome is far from certain, and note neither the state’s Constitution nor law books say voters are entitled to proportional representation based on their political affiliations.

But in an era of partisan polarization and increasingly rare ticket-splitting by voters in the state, Democrats accuse the GOP of attempting to tilt the state’s maps even further in their favor. Republican statewide candidates have on average beat their Democratic opponents by 57% to 43% over the past decade. This number acts as a proxy for party affiliation, which Montanans don’t disclose when they register to vote.

A Montana State News Bureau review of the proposed maps found that even if Democrats won every solidly Democratic district on the GOP maps, plus every district deemed “competitive” under the commission’s criteria, the GOP would still hold 68 or 66 House seats, depending on which Republican map is used. In the last session Republicans had a 67-33 majority in the House.

A supermajority would allow a unified party to independently place proposed changes to the state Constitution on the ballot, among other legislative powers. The GOP proposals, in election years more typical of the last decade’s voting patterns, would give Republicans 70 or more seats in the House.

Democrats on the state’s Districting and Apportionment Commission noted last week that both of their maps would, based on recent voting trends, result in a state House that matches the partisan makeup of Montana’s voters. They maintained they’re only asking that their candidates get a fair shake.

Squaring off last Tuesday as they launched the process of redrawing Montana’s legislative districts to account for the state’s population changes over the past decade, Democrats and Republicans on the commission found little common ground beyond their mutual distaste for “gerrymandering.”

The word is shorthand for drawing political boundaries with the goal of benefiting one party or the other. But a chasm divides the commission’s two Democrats and two Republicans when it comes to identifying whether and where that’s occurring. A fifth, nonpartisan commissioner, appointed by the Montana Supreme Court, serves in many cases as the body’s tie-breaking vote.

Republicans have generally favored what they consider a more straightforward approach to avoiding gerrymandering, emphasizing compact district shapes and following existing political boundaries.

In an interview, GOP commissioner Dan Stusek held up the Helena area on the current legislative map as an example of gerrymandering, pointing to districts that resemble arms radiating out into the conservative Helena Valley from the city’s liberal urban core. He took issue with similar-looking configurations around urban Democratic strongholds in the Democrats’ proposed maps.

“It seemed very unreasonable to suggest that … any map with a number higher than 57 (Republican-held seats) was somehow ‘extreme partisan gerrymandering,’” Stusek said.

Fellow GOP Commissioner Jeff Essmann referred to his map in less technical terms, insisting that he had simply drawn shapes in “a more free-hand approach.” Both he and Stusek said they hadn’t used any partisan analysis to create the political boundaries.

“My four guiding principles in drawing, that were in the back of my mind when I was clicking all the buttons … were the four that are legally required,” Essmann said.

Those four requirements derive from a combination of federal law, court precedent and the state Constitution. Districts must be nearly equal in population, they must be reasonably compact, they must each be in one piece and they must comply with the federal Voting Rights Act. Compactness isn’t necessarily good for Democrats, who in Montana tend to be clustered in dense urban areas. Drawing simple blocks around those districts can concentrate Democratic votes and effectively reduce their voting power.

The other goals adopted by the commission, including avoiding districts — “drawn to unduly favor a political party” — are discretionary, not mandatory. Republicans have consistently pushed back against Democrats’ insistence on drawing competitive districts.

But Democrats argue that while it’s impossible to divine a commissioner’s intent in drawing a district a certain way, a simple mathematical analysis can show what the practical effect would be, based on prior voting patterns.

That analysis, Democratic commissioner Kendra Miller, said, “is the only way to prevent gerrymandering … We look at the election data and we ask ourselves if the map is unduly favoring one party, and then we don’t adopt a map that does that.”

Miller sharply criticized her Republican colleagues on the commission for their maps, repeatedly referencing Republicans’ already substantial advantage with the state’s voters.

If the overall partisan split is 57-43 in favor of the GOP, the Democrats argue, a map that isn’t preprogrammed to generate a partisan outcome should be sending somewhere in the neighborhood 57 Republicans and 43 Democrats to the House chamber in Helena — in an average election year, at least. That isn’t the case with Montana’s current map, in which Republicans hold 67 seats in the House and nearly that proportion in the Senate.

Just 27 of the districts in each of the GOP proposals elected Democrats in a majority of the 10 statewide races identified in the commission’s “competitiveness” criteria. Republicans would likely win 71 seats and 72 seats in Stusek’s and Essmann’s maps, respectively, with the remaining districts having been won an equal number of times by both parties.

Montana’s current legislative map isn’t very competitive, under the criteria adopted by the commission, and none of the proposals would go very far toward changing that. With “competitive” defined as both parties securing wins in at least three of those 10 statewide races, just 9 of the state’s 100 House districts qualify.

The Democrats’ proposals would bump that up to 10. The Republican maps would lower it to 8.

Both Stusek and Essmann noted their proposals will evolve as voters weigh in through the public comment process.

The commission is accepting public comments on the maps through its website, mtredistricting.gov, and has scheduled a half-dozen in-person public hearings across the state. The first hearing will be held Aug. 25 in Pablo, followed by an Aug. 26 hearing in Missoula and a Sept. 1 hearing in Bozeman.

For more information, visit mtredistricting.gov/regional-public-hearings.