Who should pay to build a wall? Believe it or not, this question was asked some 2,000 years ago by the rabbis of the Talmud who, in the Tractate called Bava Batra, debated how to finance the building of a protective wall around a city. Should everyone contribute equally? Should the people whose houses would be the closest to the wall — and would, therefore, benefit most from it — pay more? Should the wealthiest contribute more than the less well off? Though the example was very specific, what the rabbis were discussing was how to establish a fair tax code.