two effects go in opposite ways: the income effect tells us that, with an income tax, the consumer feels poorer and for this reason he wants to work more, causing an increase in labor offer. On the other hand, the substitution effect tells us that free time, being a normal good, is now more convenient compared to consume and it implies a decrease in labor offer. Therefore, the total effect can be both an increase or a decrease of labor offer, depending on the indifference curve's shape. The Laffer curve depicts the amount of government revenue as a function of the rate of taxation. It shows that for a tax rate above a certain critical rate, government revenue starts decreasing as the tax rate rises, as a consequence of a decline in labor supply. This theory supports that, if the tax rate is above that critical point, a decrease in the tax rate should imply a rise in labor supply that in turn would lead to an increase in government revenue. Governments use different kinds of taxes and vary the tax rates. They do this in order to distribute the tax burden among individuals or classes of the population involved in taxable activities, such as the business sector, or to redistribute resources between individuals or classes in the population. Historically, taxes on the poor supported the nobility; modern social-security systems aim to support the poor, the disabled, or the retired by taxes on those who are still working. In addition, taxes are applied to fund foreign aid and military ventures, to influence the macroeconomic performance of the economy (a government's strategy for doing this is called its fiscal policy; see also tax exemption), or to modify patterns of consumption or employment within an economy, by making some classes of the transaction more or less attractive. A state's tax system often reflects its communal values and the values of those in current political power. To create a system of taxation, a state must make choices regarding the distribution of the tax burden—who will pay taxes and how much they will pay—and how the taxes collected will be spent. In democratic nations where the public elects those in charge of establishing or administering the tax system, these choices reflect the type of community that the public wishes to create. In countries where the public does not have a significant amount of influence