SANTA FE, N.M. (AP) — The Republican Party urged New Mexico’s state Supreme Court on Monday to strike down a congressional map that has divvied up a politically conservative oil-producing region into multiple districts as it reshaped a swing district along the U.S. border with Mexico.

The high court heard oral arguments without ruling Monday on the congressional map from Democratic state lawmakers. The Democrats say a congressional swing district in southern New Mexico remains competitive, even with the ouster of a Republican incumbent in last year’s election.

The high court’s ruling could influence which party represents the state’s 2nd Congressional District, where Democratic U.S. Rep. Gabe Vasquez is seeking a second term.

The district is one of about a dozen in the national spotlight as Republicans campaign to keep their slim U.S. House majority in 2024. Courts ruled recently in Alabama and Florida that Republican-led legislatures had unfairly diluted the voting power of Black residents. Legal challenges to congressional districts are also ongoing in Arkansas, Kentucky, Louisiana, South Carolina, Tennessee, Texas and Utah.

A New Mexico state district judge ruled in October that Democratic state lawmakers substantially diluted the votes of their political opponents, but that the changes fell short of “egregious” gerrymandering.

Appealing that ruling, the Republican Party said its substantial political minority in New Mexico is likely to be shut out of congressional representation for the entire decade before maps are redrawn again. As evidence, the GOP cited the 2022 defeat of incumbent GOP Congresswoman Yvette Herrell to a former city councilman from Las Cruces.

“Herrell was obviously an incumbent who had been on the ballot multiple times with very high name ID and she lost at the end of the day,” Harrison told the justices on Monday. “So a very Republican-favoring year, with an incumbent.”

Justices voiced skepticism, noting that Herrell lost by a thin margin of 0.7% in 2022 and also previously lost an open race for the seat in 2018 before the district was redrawn — indications that the district was competitive and may remain so.

“The actual election results, that’s the one that I’m having trouble with,” Justice Briana Zamora said.

Sara Sanchez, representing Democratic legislative leaders, said evidence in the case doesn’t support allegations of an egregious gerrymander that would entrench one party in power or deprive voters of meaningful participation.

“Every map is going to favor one party over the other in any given district,” she said. “But vote dilution only becomes a constitutional injury when it rises to the level of effectuating that entrenchment, and there just was not evidence of that here.”

Democrats hold every statewide elected office in New Mexico, along with its three congressional seats and two Senate seats.