“The dilemma of reconciling political equality with political liberty was always resolved, down to the time of J. S. Mill, by defining liberty as freedom to do everything that did not restrict the liberty of others. But when equality comes to mean economic equality―or at any rate some enforced mitigation of economic inequality―and when liberty comes to mean something like liberty of opportunity, or free and equal access to the good things which society has to offer, the relation between equality and liberty takes on a new and much more baffling complexion.”