After North Carolina's congressional district maps were thrown out by a court last week, Republicans are facing the prospect of having to draw new, fairer boundaries that could give Democrats a boost and put a handful of GOP-held seats in danger, according to experts.

Those existing maps cannot be used for the coming elections, including the March presidential primary, the three-judge panel said last Monday. Experts said that those maps are so favorable to Republicans, it would be hard for Democrats not to be helped by a court-mandated change.

"Any remotely neutral map would likely result in Democrats' picking up at least two seats in the House," said David Wasserman, House editor for The Cook Political Report and an NBC News contributor and senior analyst with the NBC Election Unit.

A Republican House candidate and two voters have filed a lawsuit in federal court to try to stop the state court injunction, but barring a complete reversal, the boundaries are likely to be redrawn this year. It will be the third set of congressional district lines North Carolina Republicans have created this decade. The Legislature designed the current maps in 2016 after a court declared the previous set, implemented in 2011, an unconstitutional racial gerrymander. The maps were drawn to ensure the same partisan breakdown of the state's congressional delegation: 10 Republicans and three Democrats.

"They have a 10-3 map in a state that is 50-50," said Michael Li, senior counsel at the Brennan Center for Justice at New York University, referring to the state's purple status. “If there’s any state where the maps need to be fixed, it’s North Carolina.”

The latest court ruling could mean several North Carolina lawmakers' seats are at risk. Republican Rep. George Holding's district neatly cuts out most of Raleigh — the most Democratic part of Wake County — and any changes there could threaten his re-election.

“He could find himself in a much more competitive district, if not a Democratic district outright,” Wasserman said.

Republican Reps. Ted Budd and Mark Walker — whose neighboring districts split Greensboro — could also be at risk.

The window for congressionalcandidates to file to run is Dec. 2 to Dec. 20, but the court said it would move the March 3 primary if necessary to make time for new maps to be drawn.

It’s unclear how that will happen. The Republican-controlled state Legislature is currently in its last week of the session, fighting over whether to override Democratic Gov. Roy Cooper's veto of the state's budget. A spokesman for state Senate President Phil Berger told NBC News that legislators didn't yet have a plan for the process, and may ask the court for more guidance before drawing new maps.

If the court sticks with the process it outlined for lawmakers to redraw state legislature maps in September 2019 — boundaries tossed out by the same three-judge panel in a 357-page ruling that amounted to a stinging condemnation of partisan gerrymandering — legislators will have to draw new maps in public hearings with the screens visible to the public to ensure transparency.

Still, whatever maps are drawn this year won't be used for long — congressional redistricting occurs every 10 years, after the census measures population changes and which states need more or less representation. And the next census is due in 2020.

While both parties have historically used gerrymandering to boost their own prospect, the last decade has seen Democrats on defense and fighting maps in the courts.

In 2010, Republicans targeted small state house races with the explicit goal of controlling the redistricting process, an effort called Project Redmap.

"He who controls redistricting can control Congress," Republican strategist Karl Rove wrote in The Wall Street Journal in 2010. The effort was hugely successful: Republicans flipped at least 19 state legislatures to GOP control, and held majorities in 10 of the 15 states where lawmakers had a hand in drawing new maps that year, according to the group leading Redmap.

Democrats have been playing catch-up ever since, but say they're determined to fight back in 2020. Former Attorney General Eric Holder is leading an effort to boost Democrats' power in the redistricting process — his redistricting group backed the lawsuit in North Carolina that got the congressional maps thrown out in the first place.

But already, Wasserman added, they're on firmer grounder after maps in Pennsylvania and Florida were tossed out by courts.

“We spent most of the decade talking about how terrible the maps were for Democrats after Republicans drew four times more maps than Democrats,” Wasserman said. “Pennsylvania, Florida and North Carolina make Republicans' task of taking back the majority [in the House] tougher by probably six seats."