That Jesus didn't speak about electing a government is beside the point; he didn't have that option. He did live in a world governed by a Torah that let the government have laws that mandated care for the poor. He lived in a world that didn't just leave it up to individuals. Sure, there was lots of private charity. That too, on top of laws.
Dr. McKnight asks his readers: "Are you seeing an increasing connection of libertarianism with the Bible? Do you think the Bible is anti-government mandated care for the poor? Do you see a radical voluntarism as the biblical model for caring for the poor?" He also presents "a set of texts that show that the Bible mandated charity and didn't leave it up entirely to individuals to make the decision." Check out the rest over at the Jesus Creed blog.
Dr. McKnight, if you gave this drash at my shul, I'd give you a hearty yasher koach!