Jan 11 (Reuters) - A panel of North Carolina judges upheld the state"s new congressional map on Tuesday, rejecting claims from Democratic voters and advocacy groups that the redrawn district lines illegally favor Republicans. The decision, which will be appealed, could have an outsized impact on the 2022 midterm elections in November, when control of the closely divided U.S. Congress will be at stake. The lawsuit, backed by Democratic and civil rights groups, had asserted that the new map ensures Republicans will win a majority of the state"s 14 congressional districts, even in elections in which more Democratic voters cast ballots. During a trial last week, experts for the plaintiffs testified that the map approved by the Republican-controlled legislature in November represented an extreme outlier, compared with thousands of computer-generated alternatives. In a 258-page ruling on Tuesday, a panel of three Superior Court judges found the evidence showed the map was "a result of intentional, pro-Republican partisan redistricting." But the judges unanimously agreed with Republican lawmakers that inserting themselves into a purely political matter would overstep their authority. Moreover, the state constitution does not expressly forbid legislators from taking partisan factors into account, the judges ruled. "Despite our disdain for having to deal with issues that potentially lead to results incompatible with democratic principles and subject our State to ridicule, this Court must remind itself that these maps are the result of a democratic process," they wrote. Lawyers for the plaintiffs immediately said they would appeal the decision, calling it "disappointing" but expressing confidence that the North Carolina Supreme Court will eventually throw out the map. The state"s top court, which has a 4-3 Democratic majority, previously delayed the primary election from March to May to allow time for the lawsuit to proceed. Federal law requires states to draw new congressional lines every 10 years to account for population shifts, after the U.S. Census completes its once-a-decade count. In most states, legislators control the process, leading to the practice of gerrymandering, in which one party engineers political maps to benefit itself. The new map would give Republicans 10 or 11 seats statewide, according to analysts, even though the state is considered a perennial battleground in national elections. Republicans currently control eight of the state"s 13 districts; North Carolina is gaining a 14th district thanks to a fast-growing population. The case is among numerous pending lawsuits challenging congressional maps in at least half a dozen states, including Texas, Ohio and Georgia, according to New York University"s Brennan Center for Justice, which is tracking redistricting litigation. Republicans need to flip only a handful of seats in the Nov. 8 elections to retake control of the U.S. House of Representatives, where Democrats hold a 221-212 edge, including vacancies. In a statement, the Republican speaker of the North Carolina House of Representatives, Tim Moore, said the maps were the result of a transparent process. "The General Assembly"s maps were drawn in the light of day, after months of public comment and feedback," he said.