I'm not sure I'd describe medicaid as "comparatively minor". Medicare is $390B, medicaid $247B ($290B including the state contributions). I guess the threshold for expenses that don't matter must bet somewhere between $290B and $390B.
http://usgovernmentspending.com/year2008_US.html#usgs30210
(Use the dropdown to select year=2008, the last year for which full data is available.)
[edit: curious why I'm being downmodded. Is posting the actual numbers so detrimental to the conversation?
edit 2: put in the federal-only numbers, thanks jbooth for pointing that out. ]