Scope v. intensity of government
Via Matthew Yglesias, Will Wilkinson asks, what is big government?
The problem with the big/small government dichotomy is that it conflates two or three measures of government. That is, the scope and the intensity of governance. Scope refers to what areas the state claims authority over: the military, transportation, public health, the environment, education, etc. Intensity refers to how strongly and effectively the state acts on the areas it claims authority over. (Intensity could be split into effectiveness and strength/intrusiveness, which is why I said "two or three.")
It's fairly clear that Republicans who complain about "big government" are referring to scope, not intensity. One element of conservative rhetoric is government is sticking its nose into somewhere it doesn't belong, like the environment, health care, etc. (Some Republicans, namely social conservatives, want to expand the scope in other directions, such as "moral values." But it's clear that these social conservatives are not really interested in the size of government.) They're not complaining about the intensity of government. Certainly they're not complaining about effectiveness. But they're not even complaining about strength/intrusiveness: on areas that conservatives agree are proper areas for state action (crime, anti-terrorism, and foreign policy spring to mind), they want the government to be as strong as possible. Longer prison sentences; more police officers; bigger military; more assertive foreign policy.
Now, historically, scope and intensity of governance have tended to increase together. Intuitively, this makes sense: if you've consolidated power well enough to rule over issue X and Y intensely, you might think about expanding the scope of your power to include issue Z as well. But scope and intensity are different concepts and should be distinguished when talking about the "size" of government.