Government: what's it for?

A quick one, for the record.  Here's what I think government is for:

1. organizing broadly beneficial collective action that doesn't arise from commerce 
2. preventing people from harming one another (including things like breach of contract, infringement on civil rights, &c)

So basically, to convince me that legislation is applicable, you have to show that either a) people are harming each other or b) the market is failing to provide something of broad societal utility.  Also, the legislation has to help.  Is there anything else government is for?  Are my criterion too permissive?