An income tax is a tax levied on the income of individuals or businesses (corporations or other legal entities). Various income tax systems exist, with varying degrees of tax incidence. Income taxation can be progressive, proportional, or regressive. When the tax is levied on the income of companies, it is often called a corporate tax, corporate income tax, or profit tax. Individual income taxes often tax the total income of the individual (with some deductions permitted), while corporate income taxes often tax net income (the difference between gross receipts, expenses, and additional write-offs). Various systems define income differently, and often allow notional reductions of income (such as a reduction based on number of children supported).

The "tax net" refers to the types of payment that are taxed, which included personal earnings (wages), capital gains, and business income. The rates for different types of income may vary and some may not be taxed at all. Capital gains may be taxed when realized (e.g. when shares are sold) or when incurred (e.g. when shares appreciate in value). Business income may only be taxed if it is significant or based on the manner in which it is paid. Some types of income, such as interest on bank savings, may be considered as personal earnings (similar to wages) or as a realized property gain (similar to selling shares). In some tax systems, personal earnings may be strictly defined where labor, skill, or investment is required (e.g. wages); in others, they may be defined broadly to include windfalls (e.g. gambling wins).

Ronald Ernest "Ron" Paul (born August 20, 1935) is an American politician who has been the U.S. Representative for Texas's 14th congressional district, which includes Galveston, since 1997, and a three-time candidate for President of the United States, as a Libertarian in 1988 and as a Republican in 2008 and currently 2012. He is an outspoken critic of American foreign and monetary policies, including the Military–industrial complex and the Federal Reserve, and is known for his libertarian-leaning views, often differing from his own party on certain issues.

A native of Pittsburgh, Pennsylvania, Paul is a graduate of Gettysburg College and Duke University School of Medicine, where he earned his medical degree. He served as a medical officer in the United States Air Force from 1963 until 1968. He worked as an obstetrician-gynecologist from the 1960s to the 1980s, delivering more than 4,000 babies. He became the first Representative in history to serve concurrently with a child in the Senate when his son Rand Paul was elected to the United States Senate for Kentucky in 2010.

Milton Friedman (July 31, 1912 – November 16, 2006) was an American economist, statistician, and author who taught at the University of Chicago for more than three decades. He was a recipient of the Nobel Memorial Prize in Economic Sciences, and is known for his research on consumption analysis, monetary history and theory, and the complexity of stabilization policy. As a leader of the Chicago school of economics, he influenced the research agenda of the economics profession. A survey of economists ranked Friedman as the second most popular economist of the twentieth century behind John Maynard Keynes, and The Economist described him as "the most influential economist of the second half of the 20th century…possibly of all of it."

Friedman's challenges to what he later called "naive Keynesian" (as opposed to New Keynesian) theory began with his 1950s reinterpretation of the consumption function, and he became the main advocate opposing activist Keynesian government policies. In the late 1960s he described his own approach (along with all of mainstream economics) as using "Keynesian language and apparatus" yet rejecting its "initial" conclusions. During the 1960s he promoted an alternative macroeconomic policy known as "monetarism". He theorized there existed a "natural" rate of unemployment, and argued that governments could increase employment above this rate (e.g., by increasing aggregate demand) only at the risk of causing inflation to accelerate. He argued that the Phillips curve was not stable and predicted what would come to be known as stagflation. Friedman argued that, given the existence of the Federal Reserve, a constant small expansion of the money supply was the only wise policy.