LINCOLN, Neb. (AP) — Nebraska lawmakers approved formal guidelines Wednesday for the redrawing of political boundaries, a process that will shape the state's legislative and congressional districts for the next decade.

The 30-16 vote was largely on party lines, with Republicans supporting the guidelines, even though Nebraska's Legislature is ostensibly nonpartisan.

Democrats, who are outnumbered and only hold seats in Omaha- and Lincoln-area districts, argued that the approved plan gives lawmakers too much wiggle room to tweak the maps for political gain.

One issue was whether to require lawmakers to preserve the cores of legislative and political districts, ensuring that most citizens remain in their existing political districts. Republicans on the Legislature's Redistricting Committee approved a change that would allow it, but not mandate it.

Another issue was how much deviation to allow when redrawing legislative districts. The approved guidelines allow for up to 10% deviation. Lawmakers rejected an attempt to lower the deviation to 8%, which would have given them less flexibility. Democratic senators argued that having more flexibility would open the door to gerrymandering.

Lawmakers aren’t expected to begin redistricting until a special session in September because of pandemic-related delays in the release of the U.S. Census population data.