Zero-SumnEqualitynThomas Byrne Edsall: The New Politicsnof Inequality; W. W. Norton;nNew York.nNothing so troubles the American pohticalnscene today as the insatiable demandsnfor equality. When the premisenof human equality was originally writtenninto the nation's Declaration ofnhidependence, most of the signers understoodnit in essentially Christian termsn(even if a . . .