What major tax-related regulation is enacted by Constitutional Amendment 16?

Constitutional Amendment 16, ratified in 1913, specifically grants Congress the authority to levy an income tax without apportioning it among the states based on population. This amendment was significant as it allowed for a more flexible and equitable tax system, enabling the federal government to impose taxes based on an individual's or corporation's income levels. Prior to this amendment, income taxes were challenged in courts on legal grounds, which created uncertainties in funding government operations. By establishing the federal government's power to tax income, Amendment 16 transformed the nature of taxation in the United States, contributing to the development of revenue generation that supports various government functions and public services.