Laffer curve and possible differences in the incentive to work for different income groups complicate the task of estimation. The structure of the curve may also be changed by policy decisions. For example, if tax loopholes and tax shelters are made more readily available by legislation, the point at which revenue begins to decrease with increased taxation is likely to become lower. Laffer presented the curve as a pedagogical device to show that in some circumstances, a reduction in tax rates will actually increase government revenue and not need to be offset by decreased government spending or increased borrowing. For a reduction
From each according to his ability, to each according to his needs in solidum is that 'everyone assumes responsibility for anyone who cannot pay his debt, and he is conversely responsible for everyone else'. James Furner then argues: 'If x = a disadvantage, and y = action to redress that disadvantage, the principle of solidarity is: if any member of a group acquires x, each member has a duty to perform y (if they can assist). All we then need to add, to get to the fundamental principle of developed communism, is to assume that non-satisfaction of a need is a disadvantage. The corresponding principle of solidarity in respect of need says: