The person who makes a tax payment is not necessarily the person who bears the burden of the tax. Today’s payroll tax is paid half by employers and half by employees, but economists agree that in the long run, the cost of the payroll tax is borne by workers; the employer part of the payroll tax simply translates, over time, into lower wages.

Today’s corporate tax is paid by companies, but as Mitt Romney said, “corporations are people, my friend,” and the corporate tax must ultimately fall on individuals. Some of those individuals are shareholders, but a portion of the corporate tax gets shifted to workers in the form of lower wages. Economists disagree on the exact proportion, but the Congressional Budget Office estimates a 75-25 split, with owners paying most of the cost of the corporate tax.

In the case of a VAT, well, as Mr. Moore says, a VAT is a tax on consumption. That means it is borne by the people who do the consuming, even if businesses are the ones submitting the forms and writing the checks.

And that makes Mr. Paul’s plan less appealing for individual taxpayers than it looks at first glance. The shift to a 14.5 percent flat income tax would mean a reduction in tax bills for many people, especially since he would repeal the payroll tax. But the 14.5 percent VAT would ultimately flow through to consumers in the form of higher prices.

Historically, American conservatives have resisted the VAT for its hidden nature, which allows governments to collect lots of revenue without taxpayers noticing too much. In Europe, VATs can be as high as around 25 percent; it is an economically efficient, easy-to-collect tax that helps make it possible to support Europe’s relatively large government sector. Mr. Paul’s choice to characterize his VAT as a “business” tax only goes to show how one can be disguised.

The former Treasury secretary Lawrence Summers once quipped that conservatives oppose a VAT because it is a money machine and liberals oppose it because it is regressive (that is, people with lower incomes pay a larger share of their income in tax, because they consume a higher fraction of their income). Mr. Summers said we would get a VAT when conservatives realize it’s regressive and liberals realize it’s a money machine. And indeed, while conservatives have historically been uneasy about VATs, Senator Paul would use his to replace revenue lost from two progressive taxes conservatives hate: corporate income tax and graduated taxes on high personal incomes.

Canada and Australia both got their VATs from conservative governments. If Mr. Paul is elected, perhaps the United States will follow in their footsteps.