Lansing — Republican lawmakers are fighting an attempt by Democratic Secretary of State Jocelyn Benson to settle a federal lawsuit alleging partisan gerrymandering in political district maps drawn by the GOP-led Legislature in 2011.

Benson and plaintiff attorneys filed briefs Thursday indicating they were "committed" to reaching a consent agreement in the federal case. Among the plaintiff attorneys is Mark Brewer, who was the Michigan Democratic Party chairman when the lines were drawn.

While details of the pending agreement are not known, the deal could lead to new Michigan legislative and congressional district maps for the 2020 election cycle and potentially force a state Senate election that would not otherwise occur until 2022, cutting short what are typically four-year terms in the upper chamber.

But Republicans in the state House and Congress are fighting the move, saying that any negotiations are being done "in secret." Benson's request to delay the trial pending a consent agreement with plaintiffs is "both procedurally improper and substantively wrong," their attorneys wrote in a Friday afternoon filing.

An agreement would "affect Intervenors rights" and the trial "would nonetheless be required to go forward regardless of what plaintiffs and the secretary may do," they said.

Attorneys Jason Torchinsky and Charlie Spies also disputed a suggestion by plaintiff attorneys that Republican lawmakers had "chosen not to participate" in the settlement discussion.

"This statement is false," they wrote, telling a three-judge panel that GOP intervenors were never invited to participate and did not reject an invitation.

"To the extent settlement discussions have been held, these discussion have occurred in secret without any offer to allow (Republican lawmakers) to participate."

Former Secretary of State Ruth Johnson, a Republican, had been defending the current political district maps approved by the GOP-led Legislature in 2011. But Benson, who took office Jan. 1, officially replaced her as a named defendant in the case this week and quickly signaled a major strategy shift.

Republican lawmakers had already won permission to intervene in the case, citing "uncertainty" over Benson's position.

Benson announced the pending settlement Thursday as part of a motion supporting Republican requests to delay the trial, tentatively set to begin Feb. 5. The suit alleges current maps violate the U.S. Constitution by intentionally "packing" or "cracking" Democrats into certain districts to benefit GOP candidates.

"It's clear the court has found significant evidence of partisan gerrymandering, and the likely outcome would not be favorable to the state," Benson said in a statement. "It is therefore my responsibility to ensure a fair and equitable resolution for the citizens of Michigan that would save taxpayers money and ensure fair representation."

Michigan House Speaker Lee Chatfield and Rep. Aaron Miller were not in office when the maps were approved in 2011 but are among the Republicans fighting the lawsuit, along with U.S. Reps. Jack Bergman of Watersmeet, John Moolenaar of Midland, Fred Upton of St. Joseph, Tim Walberg of Tipton and Paul Mitchell of Dryden.

Plaintiffs include the League of Women Voters and several Democratic voters, including U.S. Rep. Rashida Tlaib of Detroit.

The Michigan Republican Party blasted the potential settlement Friday, calling it a "blatant partisan power grab" orchestrated by Democrats, including Benson and Brewer, the former party chairman and one of the lead attorneys for plaintiffs.

"The 2019 Best Actress Oscar should go to Jocelyn Benson for promising a fair and nonpartisan Secretary of State office during the 2018 election," said GOP spokesman Tony Zammit. "With Jocelyn Benson's help, Nancy Pelosi and her friends are about to redraw our states' congressional map twice in the next two years."

It's not clear who would redraw Michigan maps if federal judges approve the pending consent agreement.

Benson said Thursday that any potential changes would only affect the 2020 election cycle. Voters in November approved a new citizen redistricting commission that will draw new boundaries for elections beginning in 2022. Benson supported the ballot measure.

"As a longtime advocate of citizen involvement in redistricting as a solution to end gerrymandering, I look forward to implementing (the commission) in a way that is transparent, nonpartisan and effectively engages citizens across the state in the important task of drawing legislative districts that comply with state and federal law," she said in a statement.

joosting@detroitnews.com