The flat tax won’t rid us of the IRS.
Only a NRST will do that,
or at least thwart the IRS from ruining individuals’ lives & livelihoods.
Tax would be collected just as all sales taxes are collected today, through the retailers.
And dumping the income tax completely is a bad idea.
The problem with a consumption tax is that when the economy tanks government revenues do too. Thus the very time that you need the government to step in and help people, government ends up in dire straits too. The income tax is far more stable than a consumption tax.
Instead raise the import tariffs until they are at least equal to the tax on domestic producers plus the cost of unemployed Americans. And reduce the income tax by an equal amount.
That would encourage industries to remain in the U.S. and relocate to the U.S.. It would put Americans back to work. It would reduce government outlays for unemployed. It would boost government revenues because more people would be paying income tax. It would boost American manufacturing capacity which could be critical during a time of war. And it would make us less dependent on foreign countries.
In the mean time, there's a good temporary alternative: a no-loophole flat tax similar to what Steve Forbes proposed in 1996. Even that would cut the yearly combined compliance and economic opportunity costs of the income tax by over 70%, a huge boon because we get several hundred billion dollars per year now available for real productive ativity.
The states should collect a minimum sales tax and give a stipend to the feds, not the other way around. Then locals could keep an eye on things to a much finer degree.