With a national sales tax we could make sure that everyone pays their fair share into the upkeep and maintanence of the United States. The millions who make money under the table don't show an income but they do need to spend money or send the money to their native homes through money services where it could be taxed.
The Federal Sales Tax would also have visitors to America pay for the infrastructure they use end enjoy as they visit America. I would also suggest that certified "MADE IN AMERICA" products be taxed at a lower rate so the American consumer can entice business back to the USA so we can finally BY AMERICAN again and be proud of it.
As an Added bonus we could abolish the IRS since we will not need to file anything ever again.
So much more to say but limited Characters.