Race and Grace: A Clarifying Question

Justin Taylor writes: "18. Reject the theories of collectivist sin, guilt, or exoneration when dealing outside of a covenantal context."  Whether I agree with this statement depends on what counts as "a covenantal context." 

At the very least, the Bible teaches that the family is a covenantal relationship, and that God therefore holds families accountable for their sins as families (see Achan, sin of).  It also teaches that the people of God are a covenant community, which he also holds accountable for corporate sin (see Ezra, confession of). 

But what about cities, tribes, and nations?  Are these also part of Justin's "covenantal context"?  I believe they should be, for the Bible often characterizes wider communities according to their besetting sins, and God judges peoples on that basis. 

In my opinion, this is all pointing us in the direction of seeing that some sins are committed by a group of people -- a principle we could extend to churches, businesses, schools, neighborhoods.  Of course it is true that each person answers to God for his or her own sin, and there is a strong theme of individual responsibility that runs right through the Bible.  But corporate responsibility is also a strong biblical theme (especially within the family of God, but not limited to that), and this responsibility readily embraces the categories of sin, guilt, exoneration, and so on.

To get back to Justin's principle on "Race and Grace," I would want a broad definition of "covenantal context."  Does Justin agree, or does he want to argue for a narrower construal.