And with this we have admitted a disadvantage of the compensation principle—­over-compensation.  We do pay excessively for property rights extinguished in the public interest.  But this is largely because the principle is employed with such relative infrequency that we have not as yet developed a technique of compensation.  German cities have learned how to acquire property for public use without either plundering the private owner or excessively enriching him.  The British application of the Small Holdings Acts has duly protected the interests of the large landholder, without making of him a vociferous champion of the Acts.

Progressive public morality readers one private interest after another indefensible.  Let the public extinguish such interests, by all means.  But let the public be moral at its own expense.

A revolting doctrine, it will be said.  Because men have been permitted, through gross defect in the laws, to build up interests in dealing out poisons to the public, are they to be compensated, like the purveyors of wholesome products, when the public decrees that their destructive activities shall cease?  Because a corrupt legislature once gave away valuable franchises, are we and our children, and our children’s children, forever to pay tribute, in the shape of interest on compensation funds, to the heirs of the shameless grantees?  Because the land of a country was parcelled out, in a lawless age, among the unworthy retainers of a predatory prince, must we forever pay rent on every loaf we eat—­as we should do, in fact, even if we transformed great landed estates into privately held funds?  Did we not abolish human slavery, without compensation, and is there any one to question the justice of the act?

We did indeed extinguish slavery without compensation to the slave owners.  But if no one had ever conceived of such a policy we should have been a richer nation and a happier one.  We paid for the slaves, in blood and treasure, many times the sum that would have made every slave owner eager to part with his slaves.  Such enrichment of the slave owner would have been an act of social injustice, it may be said.  The saying would be open to grave doubt, but the doctrine here advanced runs, not in terms of justice, but in terms of social expediency.

And expediency is commonly regarded as a cheap substitute for justice.  It is wrongly so regarded.  Social justice, as usually conceived, looks to the past for its validity.  Its preoccupation is the correction of ancient wrongs.  Social expediency looks to the future:  its chief concern is the prevention of future wrongs.  As a guide to political action, the superiority of the claims of social expediency is indisputable.

VII