Why would a politician be motivated to gerrymander congressional districts?

A politician would be motivated to gerrymander congressional districts to give himself & his party a better chance of winning an election/re-election. Gerrymandering allows for a higher chance of their bills to be passed as legislators mainly come from their own party by majority vote.

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the fourth amendment protects:

"the right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."  

so this would mean the denial to search and seizure without warrant or permission.

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.