Consider for a moment that the poor spend every dollar they make(and often every dollar they can borrow as well). If we raise their incomes by N. Some factor of

Consider for a moment that the poor spend every dollar they make(and often every dollar they can borrow as well). If we raise their incomes by N. Some factor of N dollars of demand is created in the economy by this action as they spend their increased income. Depending on the state in the rest of the economy that results in a net shift of the demand curve one way or the other. If that factor is < 1, perhaps layoffs, or increased saving, we have lower demand. But if that factor is > 1; People who spend every dollar they make are suddenly spending a few more dollars at their local WalMart every month, and so they need a few more hours of cashier each month to meet the demand, who probably spends all they make from those extra hours(in addition to the hourly raise for hours they were possibly already working). Then we will find that overall more demand has been created. Demand side arguments being made today are doing some simple reasoning and realizing that 'job creators' cannot demand labor, unless the products of that labor are demanded. We could raise the demand for the products of labor by making more income available to people who will spend it immediately. What if we raise the minimum wage(where almost all $ is spent immediately) to raise that demand at the lowest level? They're betting that the factor of created demand is near 1, and probably greater than 1. Is the idea really that complicated?