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 can be found in the Guilford Covenant in 1639: Some scholars trace the origin of the phrase to the New Testament. In Acts of the Apostles the lifestyle of the community of believers in Jerusalem is described as communal (without individual possession), and uses the phrase ""distribution was made unto every man according as he had need"" (): However, other scholars disagree with this, and claim that the phrase 'from each according to their abilities, to each according to their needs' has a non-religious origin, in 'the Roman legal concept of obligation in solidum' The Roman legal concept of obligation