What government functions seem to be growing? Are any of the categories of spending a result of the existence of externalities or the provision of public goods or the result of some other kind of market failure? Do any of the categories appear to be more

The Topic
1) Go to Budget FY 2013 - Summary Tables 

2) Review tables S-5 and S-6.

3) Review the spending by major categories in 2011, 2012, and  those proposed for 2013.

Questions: What government functions seem to be growing? Are any of the categories of spending a result of the existence of externalities or the provision of public goods or the result of some other kind of market failure? Do any of the categories appear to be more political than economic?