Supremacy
Noun and の adjective
はけん
あの男が党内の覇権を握っているのです。
That man reigns supreme over the party.
Those with the rights to leadership have complete hegemony over the country. And they will reign until the end of time.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.