What is a state called that does not give a single party overwhelming support?

The answer is swing state.  It does not support any candidate or political party.  These states can affect the course of an election as political parties do their best to gain their support which is why whoever wins this state can win the election.

in contrast, the biological controls are self-sustaining, inexpensive and very effective once established. biological control could be used on thousands of golf course acres, improving their biodiversity and quality as wildlife habitat. in the process, the golf industry will be shown to be leaders in an environmental stewardship program of benefit not only to the lands they manage but also to the watersheds in which they exist.