Flat tax. 10% across the board. No deductions, no exemptions, no credits, and no refunds, regardless of what your earnings are.
Everybody plays, everybody pays.
Eliminate federal income tax. Then, the federal government, which is a creation of the states, would be funded by direct payments from the states. The share for each state would be in proportion to the states’ number of representatives in the US House. Also, go back to senators appointed by the state governments. Of course, amendments to the Constitution are necessary.
Just a thought.