I completely agree that evangelicals often neglect social justice, MattW, and have cited them (and myself) for this in the past. Since we seem to be of different theological stripes, defining terms like 'kingdom of God' would probably get unnecessarily messy, but I think that's the source of our disagreement. I believe in a spiritual 'kingdom of God,' while your conception is probably more physical. I do, however, firmly believe that part of a Christian's responsibility to 'love his neighbor' involves the sort of social ministry to which you refer.

I also believe (and this belies my political viewpoint, not my religious one) that this sort of ministry would be more effective at a grassroots level than at the entangled, bureaucratic level...reading through accounts of the early church's extraordinary, well, socialism, I can't help but chuckle at how wretched it would've turned out had they appealed to Rome to prop up their ministry.