Why does the party seek power and what is the basis of the party's world?

In 1984, the party's only motivation for control is power. That is it. The party wants perennial uninhibited power.  The are no ideological motivations, O'Brien says that was the flaw of most old world orders, or leader worship. In the end, O'Brien argues , there is only power for the sake of power.   

The Party seeks power entirely for its own sake. We are not interested in the good of others ; we are interested solely in power. Not wealth or luxury or long life or happiness: only power, pure power.