Kansas legislators should try harder to equalize the number of residents living in each Kansas House and Senate district.

When redrawing the state’s U.S. House districts, legislators are required by law to strive for “zero deviation,” which would place the exact same number of residents in each of the state’s congressional districts. An exact balance is impossible to achieve, but it’s a good goal that requires lawmakers to do the best job they can to equalize population among districts.

Last week, however, the House Redistricting Committee voted to accept a population deviation of up to 5 percent when redrawing state legislative districts. Based on numbers from the 2010 Census, the perfect size for a Kansas House district is 22,716. A 5 percent deviation would be 1,136 residents. That means the committee would accept districts with populations that ranged from 5 percent below the ideal (21,580) to 5 percent above (23,852). That’s a pretty significant difference.

A couple of factors are likely to make the population differences among legislative districts even bigger before the next redistricting process 10 years from now.

New census figures show a significant population shift from rural areas of the state to urban areas, which is likely to continue in the next decade. For instance, the 38th District, represented by Rep. Anthony Brown of Eudora, now has 40,677 residents while the 117th District in Hodgeman County in western Kansas has only 18,133. Even if the redistricting committee redraws district lines now to exactly equalize the size of those districts, chances are a continued rural-to-urban shift will cause them to be significantly unequal in 10 years. Accepting a 5 percent deviation in the size of those districts now is likely to aggravate that problem.

Cities that are the home of major universities or military installations, including Lawrence and Manhattan, also could argue that their residents already are under-represented because of a state law that allows students and military personnel to choose to be counted in their “home” communities in another city or state instead of in the communities where they actually live most of the time. The state’s 2010 census adjustment subtracted about 12,000 residents from Douglas and about 11,000 from Riley County. That deviation only adds to the 5 percent deviation that legislators say they will accept when redrawing districts.

Rep. Caryn Tyson, R-Parker, argued that “It is not feasible to keep counties and towns together” with a zero deviation. It’s not possible to keep entire cities together if they are larger than about 24,000 residents. Splitting a county between two legislative districts seems like a minor problem.

“People are protecting their own interests,” concluded Rep. Brown, a fellow Republican.

It’s natural for representatives to try to protect their own turf in redistricting, which often is called the most politically driven activity state legislators handle. Redrawing district lines isn’t easy, but striving for the best possible population balance in individual districts is a basic part of the job. If state legislators can do it for congressional districts, which involve far greater population numbers, they should be able to do the same for the state’s legislative districts.