Shame on you for deliberate deception.
Adam Smith's complete quotation (which you carefully prune) reads: ""The necessaries of life occasion the great expense of the poor. They find it difficult to get food, and the greater part of their little revenue is spent in getting it. The luxuries and vanities of life occasion the principal expense of the rich, and a magnificent house embellishes and sets off to the best advantage all the other luxuries and vanities which they possess. A tax upon house-rents, therefore, would in general fall heaviest upon the rich; and in this sort of inequality there would not, perhaps, be anything very unreasonable. It is not very unreasonable that the rich should contribute to the public expense, not only in proportion to their revenue, but something more than in that proportion"" "Wealth of Nations," Book V, Chapter II, Part II, Article I, pg.911 http://en.wikiquote.org/wiki/Adam_Smith
In this passage, Smith is not recommending a flat tax (as you allege) but goes categorically beyond flat taxation with a frank proposal for progressive taxation.
American "conservatism's" linchpin penchant for self-destruction resides in its ubiquitous determination to de-contextualize "shards of truth" in order to promote essentially deceptive positions.
Here is what full contextualization looks like: " Republican Rule and Economic Catastrophe – A Lockstep Relationship." http://paxonbothhouses.blogspot.com/2012/05/republican-rule-and-economic.html
Will you post my comment in its entirety?
I rest my case.
Attentively, Alan Archibald
Hillsborough, North Carolina