Many of our current problems would disappear.
Unfortunately, given the current size of the federal government, that sales tax would likely be a monster. For example, the Fair Tax solution would be 30% on all goods and services, a rate high enough that all earners would get a basic government check — the largest welfare program in the country — to cover basic expenses. And some people estimate that that 30% wouldn’t be enough; you would need something as high as 50% to 60%.
A principled conservative by the name of Bruce Bartlett has estimated that once your sales tax goes up above 10%, you start to get significant diversions into black market activity.
Such a fair tax is much better imposed at the state level, IMO, where the budgets are a tiny fraction of the federal budget.