It is one of the tasks given to the fed in the constitution. I generally prepare to skoff any time somebody uses the phrase "expanding government". That's such a bizaare term. If they spend more money but don't hire anymore people is that expanding? What about vice versa? What about idjit laws?
big government-when the government spends more money (like in a war) but does not seize more power
Big Government-is when they seize more power away from the people (as in federalizing airport security
However, other than the airport security, and the patriot act (which has its goods and bads), it has been relatively the former