According to the Article I, Section 8 of the Constitution, Congress has the power to lay and collect taxes for the common defense and general welfare of the United States. Thus, tax laws need to be applies nationwide and not only in some States. For example, in 2017, the Congress approved a tax cut for corporations and individuals. Corporations' tax went from 35% to 21% and individuals from 39.6% to 37%, this was one of the promises in president Trump's campaign.
