COLUMBUS, Ohio (WCMH) — With a party-line vote in the state Senate Tuesday afternoon, Ohio Republicans’ latest proposal for a new congressional map is now just a few steps from becoming law.

Ohio’s current congressional districts split 12-4 Republican, despite GOP congressional candidates winning about 54% of the vote in statewide elections under the current map. After Ohio loses a seat next year due to low population growth, Republicans’ new map would have Ohio’s 15 districts splitting 12-3 Republican.

Using data available from Dave’s Redistricting App, a nonpartisan website that analyzes congressional district maps, NBC4 visualized Ohio Republicans’ map — Senate Bill 258 — to a street level, adding color and pop-up information to show districts’ partisan makeup.

Use the interactive below to zoom in and explore:

Although a 15-district map better aligned with Ohioans’ voting history would favor Republicans 8-7 or 9-6, GOP senators’ proposal includes six districts that are considered competitive (a party’s advantage being less than 10 percentage points). The current map has just three such districts.

Competitive or controversial?

The Ohio Constitution dictates maps be drawn with four main goals in mind: Districts should be compact, contiguous and proportional, and they should preserve political subdivisions like cities.

“The map in front of you is not only constitutionally compliant, but it is also the most competitive map offered by any caucus to date,” state Sen. Rob McColley (R-Napoleon) said Tuesday in floor debate. “It also splits the least counties out of any map that’s been introduced in the Ohio General Assembly, and it keeps Ohio’s largest cities whole.”

But where the map succeeds in keeping districts compact and cities together, Democrats say it unfairly favors Republicans at the ballot box.

“Maps that are passed by a simple majority must not unduly favor a political party,” state Sen. Tina Maharath (D-Canal Winchester) argued. “And it’s painfully clear that a map designed to produce 12 Republican districts out of 15 does unduly favor one party.”

The nonpartisan Princeton Gerrymandering Project gives the map an ‘F’ grade for its “significant Republican advantage.”

SB 258 passed by a 24-7 vote Tuesday, with only Republicans voting for and only Democrats voting against, after about an hour of floor debate. Republicans released their map late Monday, giving the public and opponents just hours to review it before a Tuesday morning committee hearing and the afternoon vote in the full Senate.

“Ohioans have been rushed throughout this whole process trying to submit testimony with just little notice, only to have their opinions ignored,” Maharath said.

The Republican map’s next steps

For a map to last the full 10 years until the next U.S. census, it needs bipartisan support: 60% of lawmakers in each chamber and 33% of Democrats. But since no Senate Democrats voted for SB 258, this map would only be in service for four years if enacted.

The Ohio House of Representatives, which Republicans control 64-35, is expected to hear the bill in committee on Wednesday and fully vote on it Thursday. If approved without changes, it goes to Republican Gov. Mike DeWine to sign.

The deadline for a new congressional map is Nov. 30. Since the General Assembly doesn’t plan to meet during the week of Thanksgiving, lawmakers are scheduled for session Wednesday, Thursday, and Nov. 29 and 30.