Why do republicans say they want to limit government's power...?

yet when elected they make the most use of the powers defined and undefined? For example corporations say that government's laws and policies are an intrusion into the affairs and effective running of their firms,yet they rely on ambadors via the president to get help in market expansion or help from congress to get a law ped that would help their profit margins or like Bush showed the world help to acquire resources that ordinarily wouldn't have been available (deadlocked oil anyone?),another example,if the powers of government had been so deregulated do you think Bush would have been able to get America into our "peacekeeping" role? i highly doubt it,what do you think?