Economist: the personal income tax in the United States is a progressive tax, and the tax law is extremely complicated. People who want to pay taxes honestly often make mistakes in declaration because of misunderstandings, while people who deliberately evade taxes can always find loopholes in the tax law. Generally speaking, the space of tax avoidance is proportional to the complexity of the tax system, and the ability of tax avoidance is proportional to the level of taxpayers' income. Most of the tax avoidance space caused by the complex tax system will be used by the rich, so that the progressive tax can not reach the progressive degree stipulated in the tax law, and its function of regulation and distribution is also greatly weakened.
The statement 'In 1981, Americans put forward the idea of abolishing the progressive tax rate and implementing a single tax rate' provides the strongest support for the above argument of economists.