In a comment on this post, my dear brother Joe suggested I take a look at what the Scripture really says about taxation and government. It's a good suggestion, so let's have at it.
First of all, you've got the fact that at least one tax collector promised to repay the money he'd stolen when he came to Christ. This is unremarkable until one considers that the major part of the compensation of tax collectors was whatever they could gouge out of the taxpayers; in other words, if tax collectors in Rome were to be honest, there would be a lot less demand for that job--and most likely far fewer taxes collected due to a different kind of person collecting them.
Along the same lines, John the Baptist told Roman soldiers to be content with their pay. Just as tax collectors got rich by theft, so did soldiers become wealthy by pillage--the "salarius" they were ordinarily paid was a ration of bread and salt, so being content with their pay more or less meant they would no longer be about the business of pillage. Obviously, this also would have huge implications for Roman government, which lived on the fruits of pillage. When expansion stopped as the Visigoths and Huns were able to stop Roman legions, the flow of money, food and goods upon which Roman society relied stopped as well.
Hence, we can infer from the historical context that as people followed our Lord, critical parts of Roman society would have quickly collapsed. Now this is, to be sure, descriptive--the only prescriptive passages for government in the New Testament I'm aware of are Romans 13 and 1 Peter 2:13-17, along with Christ's command to pay Caesar his due (there's that tax collection question again).
It's worth noting, of course, that the primary justification Paul and Peter give for obeying government is that the government is responsible for punishing the wicked and commending the just. Understanding the limitations of arguing from what a text doesn't say, it's worth noting that the Scriptures neither commend nor condemn the Roman welfare state. That said, it's also worth noting that the welfare state of Rome more or less ended with the city limits of the capital, and that Paul told the Thesssalonians that if a man would not work, neither should he eat.
From the New Testament, then, we can conclude that public safety is a Biblical purpose of government, and also that the practice of empire--especially paying soldiers by plunder--does not appear to be consistent with the Gospel. We might also infer that any welfare for able-bodied people is contrary to what Paul told the church.