<P> Gerrymandering can also be done to help incumbents as a whole, effectively turning every district into a packed one and greatly reducing the potential for competitive elections . This is particularly likely to occur when the minority party has significant obstruction power--unable to enact a partisan gerrymander, the legislature instead agrees on ensuring their own mutual reelection . </P> <P> In an unusual occurrence in 2000, for example, the two dominant parties in the state of California cooperatively redrew both state and Federal legislative districts to preserve the status quo, ensuring the electoral safety of the politicians from unpredictable voting by the electorate . This move proved completely effective, as no State or Federal legislative office changed party in the 2004 election, although 53 congressional, 20 state senate, and 80 state assembly seats were potentially at risk . </P> <P> In 2006, the term "70 / 30 District" came to signify the equitable split of two evenly split (i.e. 50 / 50) districts . The resulting districts gave each party a guaranteed seat and retained their respective power base . </P> <P> Prison - based gerrymandering has occurred in places such as New York when prisoners were counted as residents of a particular district, increasing the district's population with non-voters when assigning political apportionment . This phenomenon violates the principle of one person, one vote because, although many prisoners come from (and return to) urban communities, they are counted as "residents" of the rural districts that contain large prisons, thereby artificially inflating the political representation in districts with prisons at the expense of voters in all other districts without prisons . Others contend that prisoners should not be counted as residents of their original districts when they do not reside there and are not legally eligible to vote . This is past - tense after August 11, 2010 . </P>

An outside party would be more likely to be called in for the