1) Partisan 2) Partizan 3) Tendencious 
designed to advance a cause
[adj] - having or marked by a strong tendency especially a controversial one
tendentious Characterized by a deliberate tendency or aim; especially, advancing a definite point of view.
tendencious adjective having or marked by a strong tendency especially a controversial one; `a tendentious account of recent elections`; `distinguishing between verifiable fact and tendentious assertion`
[Obscure words] having a strong bias, especially a controversial one