For most Americans, redistricting is a study in bare knuckles partisanship as political parties battle for the advantage that comes from reorganizing congressional and state legislative districts.

Not in Iowa.

Not only is our redistricting process essentially nonpartisan, but it produces cohesive, manageable districts and meaningful electoral contests -- and has been doing so since 1981.

Elsewhere, partisan gerrymandering has produced more and more districts so skewed to one party that elections are almost meaningless. Some analysts believe races for only 100 of the 435 seats in the U.S. House of Representatives are competitive enough to give voters a real choice.

In Iowa, the 2001 redistricting produced four competitive congressional races out of a possible five, and the proposed 2011 map is likely to mean three competitive districts out of four.

How does Iowa do it?

In 1980, the Iowa legislature gave responsibility for drawing up redistricting plans to the Legislative Service Agency, a nonpartisan state agency that also manages the legislative library, computer services and legal drafting.

It also established a Temporary Redistricting Advisory Commission of four members appointed by the House and Senate majority and minority leaders. The commission's chairperson, elected by the appointees, cannot hold a partisan political office or political party office, work for the legislature or be related to or employed by a state or federal legislator.

By law, the Legislative Service Agency starts with population equality (one man, one vote) as the most important criteria for a new map. Whenever possible, it must set district boundaries that match the boundaries of political subdivisions such as counties and keep to a minimum the number of counties or cities split into more than one district.

Iowa law further requires that districts be reasonably compact in shape -- defined as "square, rectangular, or hexagonal ... and not irregularly shaped," and there are factors the agency is prohibited from considering.

Its maps may not favor one political party or incumbent or attempt to dilute or augment the voting strength of a language or racial minority group.

The Iowa Supreme Court also has ruled out redistricting that attempts to preserve districts or avoid joining part of a rural county with an urban county.

To enforce those restrictions, the Legislative Service Agency is barred from considering voter registration data, officeholders' addresses, previous election results or population data other than census head counts.

By April 1, the agency submits its first plan to the legislature. The advisory commission begins public meetings to hear citizen comments (this year it held five) and submits a report within 14 days. The legislature must then wait three days before conducting an up-or-down vote on the plan. If passed, it goes unchanged to the governor for his signature or veto.

Otherwise, the Legislative Service Agency submits a second plan within 35 days, taking into account any reasons cited for the defeat. Again, the legislature votes on it without amendment.

If the second plan also fails, the agency again has 35 days to submit a third plan. This time, the plan is subject to amendment by the legislature, but must still meet all of Iowa's redistricting criteria.

A final deadline keeps pressure on the legislature to get the job done: If no plan is enacted by Sept. 1, responsibility for state legislative redistricting shifts to the Iowa Supreme Court. (If a new redistricting plan is not approved in time for the next congressional election, the U.S. Constitution provides for all representatives to run on a statewide basis.)

Iowa's track record: Redistricting plans have passed successfully on the third (after the 1980 census), first (after the 1990 census) and second attempts (after the 2000 census) and have never been challenged in court. The Legislative Service Agency's first redistricting draft is expected to pass this year, even though it will pit two incumbent Democratic congressmen against each other in one district and two incumbent Republicans in another.

Steffan Schmidt, an Iowa State University political scientist known as "Dr. Politics," sees Iowans' political culture, which emphasizes fairness, as a key contributor to the system's success. His observation is borne out when you hear Iowa politicians talk about this year's plan.

"I see a pathway to Republican control. I can also see a pathway to Democrat control," says Iowa House Speaker Kraig Paulsen, a Republican. "That tells me maybe there's a heightened level of fairness."

"We both kind of don't like what we see," which probably means it's a fair plan, says Senate Democratic Leader Mike Gronstal.

A vote is expected this week.

Edith Munro, an Iowa-based freelance writer and former congressional staff member, reports on political, environmental and agricultural topics.