Why monetary control in capitalist economies fails? Endogenous money approach, according to Wray and taking Keynes's nominalist view into consideration, could answer this. Money is a balance sheet's script in transferring purchasing power, a term in which debt positions are described, and its asset item thus financed on demand by banking system. Historically and institutionally, endogenous money is a nominal asset that circulates in every sort of giro systems. Wallerstein's World-System might be reinterpreted in view of its wobbly circulation towards the World- (Giro) -System. Money supply cannot be controlled exogenously since it is determined by private decisions to enter into debt commitments for spending. Liabilities are contractually fixed but assets are indeterminate thus cyclically could fall. This nominalistic nature of monetary contracts is based on the characteristics discussed bellow. Such uncertainties in turn make liquidity preference volatile, whose constraints will emerge, as it were, quasi-exogenously. The latter is no way identified with the demande for money, nor met with the money supply. Financial instability in capitalism is therefore due to a dynamics between the endogeneity of money supply and the "quasi-ex-ogeneity" of liquidity preference. This view on monetary theory provides a compelling critique of financial liberalization.