However, state law increasingly restricts inappropriate bias. In 2010, only eight states directly regulated partisan outcomes in the redistricting process (instead of trying to achieve compromise or balance through the structure of the redistricting body); Now, the constitutions or statutes of 19 states speak for state districts, and 17 states do the same for congressional districts. Much of the scientific and popular attention to district reclassification is related to the partisan outcome of the process, although partisan effects are not the only important effects. All states must comply with federal constitutional population and anti-discrimination requirements. For congressional redistricting, the allocation clause in Article I, Section 2 of the U.S. Constitution requires that all districts be as close to the population as possible, which essentially means exactly the same thing. For state districts, the equality clause in the 14th Amendment to the U.S. Constitution requires districts to be substantially equal. Some say that a 10% deviation of the population from one district to another is a safe standard. However, this has not proven to be a guaranteed protection against judicial review or review.
Several countries have their own deviation standard. For example, Colorado districts prohibit a population variance of more than 5% (Colo. Const. Art. V, § 46). Although this system may seem confusing, the main rules are listed in the paragraphs below. Each rule is accompanied by an example of how it is applied or manifested. There are three other notable structural rules that govern the location of county lines in some states. In the League of United Latin America. Citizens v. Perry, 548 U.S. 399 (2006), the Texas legislature passed a new redistricting plan in 2003.
Voting rights supporters challenged the cards and filed partial lawsuits under Section 2 of the Voting Rights Act, claiming Texas Congressional District 23 was diluting the ability of Latino voters to vote for a prime candidate by dividing the growing Latino community in this part of Texas among several districts. The Supreme Court found that the plan violated Section 2 of the Voting Rights Act because the growing Latino population in District 23 had historically been discriminated against in voting, and that the state`s district plan «deprived Latinos of the ability to exercise their ability to elect candidates of their choice in District 23.» The other major federal rules relate to race and ethnicity. The extent to which redistribution can or should take into account race and ethnicity is sometimes seen as a particularly sensitive issue, but that is partly because some people have a vested interest in making it seem difficult. Race relations and electoral politics are both quite complicated. But the law of race and ethnicity in the context of reclassification essentially boils down to three concepts. And while there are, no doubt, some complications in the details – including some hurdles for challengers trying to challenge cards in court – the overview is fairly straightforward for those drawing the lines. The Federal Constitution sets few practical limits on redistricting bodies. Individual districts can be drawn to favor or discriminate against candidates of a particular party or individual incumbents or challengers (in fact, the court explicitly blessed the lines to protect incumbents and even those drawn for a small partisan advantage).
As for the county plan as a whole, the Supreme Court ruled unanimously that excessive bias in the process is unconstitutional, but the court also said federal courts cannot hear allegations of undue bias because they cannot decide how much is «too much.» In practice, compactness is more in the eye of the beholder. Idaho, for example, says its redistricting commission should «avoid drawing strangely shaped districts» — which is more specific than most states. Only 7 states seem to specify some degree of compactness: Arizona and Colorado focus on distorted borders; California, Michigan, Missouri and Montana focus on dispersal, albeit in different ways; and Iowa embraces both. In addition to these binding standards, which are set forth in the U.S. Constitution and the Voting Rights Act, states are authorized to establish their own criteria or principles for developing plans. Principles or criteria may be found in state constitutions or laws, or passed by a legislature, house or committee, or by a court called upon to develop a plan if the legislative process fails. During reclassification, state legislators or redistricting commissions are assigned certain criteria with which boundaries can be drawn. These criteria are intended to make districts easily identifiable and understandable and to ensure equity and consistency. Legislation on country-specific redistribution criteria is common.
Many of these bills propose to prohibit the use of political data or the adoption of concepts such as competitiveness. Few redistricting concepts are absolute, and adjacency is no exception. Many states require adjacency only «to the extent possible,» and courts generally accept anomalies that otherwise appear reasonable in their context. For example, the town of Racine, Wisconsin, has a non-contiguous border (borders like these are fairly common byproducts of annexation). Thus, in 2001, the legislature moved the 61st District of the Wisconsin State Assembly to incorporate most of the town of Racine – with a non-contiguous part of the district encompassing the non-contiguous part of the city. In 2011, the 47th District of the Wisconsin State Assembly did the same for the noncontiguous parts of Blooming Grove and several other noncontiguous counties, and the 60th District of the State Assembly did the same for the noncontiguous parts of Cedarburg. While district redistribution is a state task, the Supreme Court plays an outsized role in this process, often taking over redistricting cases – almost every session. Many cases are based on the interpretation of these criteria. Finally, other criteria could define the timing of the maps, the degree of variation accepted in the population, or the data used for reclassification. For example, a handful of states adjust census data before beginning the process of deporting students or relocating incarcerated people to a home address. By law, the 43 states with more than one representative must redraw after each decennial census to account for population movements within the state and (if necessary) add or remove congressional districts.
  States are not precluded from redrawing districts at any time between censuses until each congressional election, provided that such redistribution complies with various federal laws.  However, proposals to reorganize districts «in the middle of the decade» (as in Texas in 2003) were generally highly controversial. Another case of intercensal redistribution occurred between the 2016 and 2018 elections in Pennsylvania.  Districts cannot cross county, city or city boundaries. Sometimes counties or cities need to be divided to meet other redistricting requirements. However, many state laws do not specify «whether it is better to minimize the number of jurisdictions that are divided or the number of cases with which a particular jurisdiction is divided.» Preservation of counties and political subdivisions is necessary when redistricting state districts in 34 states and when redistricting congressional districts in 15 states. Those who have the Redistricting pen do not have a blank board to draw the lines. Various rules limit the boundaries of districts that may or may not be drawn. Rules on equal voting rights for populations and minorities are backed by the federal government (although states can add additional restrictions). But even after factoring in federal rules, there are countless ways to divide a jurisdiction into districts. State constitutions – and sometimes state laws – include additional rules for drawing borders.
State and federal judicial systems are often involved in resolving disputes over legislative and congressional reorganization when the impasse prevents timely realignment. In addition, people disadvantaged by a proposed district plan can challenge it in state and federal courts. Justice Department approval (known as prior authorization) was required under Section 5 of the Voting Rights Act of 1965 in some states that historically had racial barriers to voting. The Supreme Court`s decision on Pennsylvania`s redistribution allows elected officials to choose their voters by eliminating most of the reasons voters challenge county boundaries.  In 25 states, the state legislature has primary responsibility for creating a redistricting plan, in many cases subject to state governor approval.  To reduce the role that legislative policy could play, thirteen states (Alaska[a], Arizona, California, Colorado, Hawaii, Idaho, Michigan, Missouri, Montana, New Jersey, Ohio, Pennsylvania, and Washington) determine the reorganization of Congress by an independent or bipartisan redistricting commission.  Five states: Maine, New York, Rhode Island, Vermont[b] and Virginia give independent bodies the power to propose redistricting plans, but retain the role of legislators in approving them. Arkansas has a commission consisting of the governor, attorney general, and secretary of state.