Amid the closest partisan margin in the House of Representatives in almost 20 years, state legislatures are redrawing their congressional districts in preparation for the 2022 midterm elections.

States are constitutionally required to redraw their congressional districts following the release of the U.S. census, but the manner in which they do so is set at the state level. As a result, legislators move to ensure that their districts will be as safe for lawmakers of their own parties.

A majority of congressional districts will be drawn by partisan lawmakers, a FiveThirtyEight analysis found, with 187 of those districts drawn by Republican state legislatures. Democrats will only control the redistricting process for 75 seats, and 167 more will be drawn by independent commissions. (RELATED: Republicans Hold Majority State Legislatures, Potentially Giving Them An Advantage In Redistricting Process)

In states like Indiana and Texas, where redistricting is controlled by the Republican Party, map-drawers have chosen to shore up existing GOP seats. A map introduced in the Indiana state House would maintain the GOP’s 7-2 advantage in the state’s House delegation. Instead of redrawing Democrat Andre Carson’s Indianapolis-based district to make him vulnerable to a challenger, the proposed map shores up Republican Victoria Spartz’s suburban Indianapolis district. Spartz won her election in 2020 by only four points.

“I think they just made sure that they further entrenched where they felt maybe they needed it,” Indiana University professor Marjorie Hershey told The Associated Press of the map.

Texas is taking a similar approach to redistricting. Republicans in the legislature introduced a map Monday that would add the state’s two new seats to deep blue Austin and Houston. Despite creating two safe Democratic seats, Republicans would still likely expand their margin in the House delegation from a 10 seat to a 12 seat advantage.

NEW: How do Rs plan to keep TX red/save incumbents in redistricting?

By packing Dems in 3 new safe blue seats. They’ll likely add 1 in Austin area & turn Dallas/Houston seats of Reps Colin Allred + Lizzie Fletcher into Dem vote sinks

Could see map todayhttps://t.co/O7WessjEnu

— Ally Mutnick (@allymutnick) September 27, 2021

During redistricting, the preferences of voters are often lost, elections scholar Walter Olson told the Daily Caller. Olson is the Republican co-chair of the Maryland Citizens Redistricting Commission, a nine member board tasked by Republican Gov. Larry Hogan with drawing congressional districts for the state.

In contrast, Maryland’s commission is designed to maximize voter input, Olson explained, including holding public meetings where residents can explain what they want for their districts.

“I think we’re up to 10 or 12 meetings where the public can sound off,” he noted. “From an early stage, residents of one rural county thought that we had not drawn lines correctly, and so we heard from a large number of them at our most recent public hearing urging us to change that.”

“We have had dozens of maps submitted by members of the public, both for the congressional maps that we’re drawing and for the state legislature maps.”

Viewing publicly submitted maps “helps convey to the public what our principles are,” Olson said. “The fact that not breaking counties is very important to us, that’s part of the language in Gov. Hogan’s executive order and it also tracks Maryland law in some respects.”

Maryland voters also oppose splitting counties, and would prefer more compact congressional districts, he added.

“Gov. Hogan has made a continual theme, since he campaigned for governor the first time, to fix Maryland’s terrible record of gerrymandering, which is one of the worst in the country,” Olson explained. “The majority of Marylanders, Democrats, Republicans, and independents alike, favor the idea of an independent commission, not consisting of politicians, not driven by politicians’ interests, to draw the lines, so as to reduce the conflict of interest of letting the insiders do it for their own benefit.”

Following the 2010 census and subsequent redistricting, Maryland and North Carolina tied as the most gerrymandered states, a Washington Post analysis found. Maryland’s Third District, drawn to protect Democratic Rep. John Sarbanes, was the second-most gerrymandered district in the country. It is only contiguous when the Chesapeake Bay is included as part of its boundaries.

Maryland also redrew a formerly Republican district in the western part of the state to become safe for a Democrat in 2010. The state’s House delegation moved from six Democrats and two Republicans to seven Democrats and one Republican as a result of the choice.

Also expected at Wednesday’s meeting: a discussion of the current base Congressional map (pictured) to decide whether it or some other map commands a consensus. /5 pic.twitter.com/PlWwXWqK70

— Walter Olson (@walterolson) September 21, 2021

Olson also said that Maryland’s racial makeup makes drawing compact districts more difficult. The Supreme Court ruled in the 1986 case Thornburg v. Gingles that the Voting Rights Act could require state legislatures to draw majority-minority districts to prevent the “loss of political power through vote dilution.” Two of Maryland’s districts, the Fourth and Seventh, are majority African-American, while the Fifth District does not have a racial majority.

“Compliance with the Voting Rights Act (VRA) comes above the other criteria alongside only population equality, which is a constitutional aspect. We know that obeying and complying with the VRA needs to take precedence if there is a trade-off between one of the important but second-order values like compactness. We need to have a plan that will pass muster under the VRA,” Olson said, adding that “the courts have not come out with very clear guidance” on VRA compliance.

The commission only acts in an advisory role to Hogan. Unlike the 16 states where commissions have absolute authority to set district boundaries, the maps drawn by the Maryland Citizens Redistricting Commission may not be approved by the state legislature.

However, Olson said that political considerations are not part of the commission’s work.

“That’s not what we’re being charged to do. We’re being charged to draw fair and impartial maps, and let others take it from there.”