This summer, the midterm landscape is being shaped as much by district lines as by candidate campaigns. In the last year, ten states have changed their congressional maps (Alabama, California, Florida, Louisiana, Missouri, North Carolina, Ohio, Tennessee, Texas and Utah), marking an unusually aggressive wave of mid-decade redistricting. The result is that this year’s primaries are not just routine candidate-selection contests. They are the first tests of newly drawn political geography: which communities were grouped together, which incumbents were displaced, and which races have become so safely partisan that the primary may be the decisive election.

Texas’ new map was designed to give Republicans an advantage in five Democratic-held seats, while North Carolina’s new map strengthened the GOP position in several districts. Florida is now moving into the same category. The Florida Supreme Court declined to block a new Republican-drawn congressional map, all but ensuring it will be used this fall. Reuters reported the map is aimed at flipping as many as four Democratic-held seats, with Florida’s primary scheduled for August.

Missouri and Ohio are also important states to watch. Missouri’s new map dismantles the Kansas City-based Democratic district held by Rep. Emanuel Cleaver and gives Republicans an advantage in seven of the state’s eight districts. Ohio’s new map, while framed as a compromise, still improved Republican positioning in districts held by Democrats such as Reps. Greg Landsman and Marcy Kaptur. On the Democratic side, California is the major counterweight. The U.S. Supreme Court allowed California to use a voter-approved map designed to give Democrats five more congressional seats.

Several other AHPA-footprint states didn’t redraw, or likely cannot in time for 2026. Georgia Republicans declined to move forward with congressional redistricting in a June special session, potentially shifting any renewed effort to 2028. Kansas Republicans backed away after leaders said they lacked votes to override Gov. Laura Kelly’s expected veto. Colorado’s June 30^th  primary, Wisconsin’s August 11^th primary, and the remaining contests in Hawaii, Washington, Kentucky, Oregon, Illinois, D.C. and Maryland are therefore more about primary electorate composition than new congressional lines. Wisconsin’s Supreme Court has agreed to hear appeals over the congressional map but an outcome is not expected before the November elections.

The policy consequence is straightforward: the next Congress may be shaped less by broad general-election persuasion and more by who survives maps designed to predetermine partisan outcomes. The practical question for the rest of 2026 is not only which party benefits from the new lines, but how those lines change the incentives of the members who will write, oversee and fund federal health policy in 2027.