Simplify federal tax on income to be the same percentage for ALL people (citizens, residents, non-residents, illegal immigrants, EVERYONE) no matter where their income comes from.
Banish credits, rebates, deductions - they are all loopholes. Let people pay the same portion of their "income" and choose what to do with the REST of THEIR money.
Stop the wealthy from sheltering their income and prevent those with copious dependents from using that as a reason NOT to pay their share of taxes.
Want to save for retirement? Want to have 10 kids? Want to have a huge house and ride a bike to work? Want to have cheap housing and expensive car? No problem! Just pay your portion of your federal taxes and do what you want with the REST of your money.
Stop funding the lifestyle choices of others!!