turf war
1. An ongoing fight among factions, often criminal ones, attempting to control a particular territory (i.e. their "turf"). Primarily heard in US. The neighborhood has been torn apart by the turf war between the two gangs.
2. By extension, a dispute or hostile environment among persons or factions competing for a particular position, or influence in a particular area. The school newspaper has become the scene of a turf war among several ambitious students who all want to add "editor" to their college applications. The electoral map has become nothing more than a diagram of the turf war between the two parties.