You've Tried Just War, Now Try Just Tax

I like it. The story begins with France's complaint that Switzerland is "raiding" its neighbors by keeping its tax rates low and noting
"Tax harmonization" in the EU, incidentally, never means lowering tax rates. It invariably involves raising taxes to the same high level. It was on this basis that, when faced with companies leaving Germany to base their headquarters in 19 percent flat-tax Slovakia, Germany's ex-chancellor Gerhard Schroeder once accused Slovakia of "un-European" behavior. To be truly European, apparently, means giving about half your income to the government.
Then it gets interesting. Drawing on debates in 16th. c. Spain, the author notes:
Spanish theologians such as Pedro de Navarra insisted that it was not enough for governments to legislate a tax for it to be considered just. Tax laws, they argued, must meet other criteria of justice. Was there a genuine need for a new tax? Were the proposed taxes proportionate and equitable? Were they moderate or excessive?The same scholars claimed that imposing taxes to support wasteful government expenditures was immoral, even tyrannical. In some cases, they added, people could rightly refuse to pay, especially when taxes were taking nations to the edge of financial ruin.
Ooh, and I can think of other questions, such as does the tax "incentivize" the black market? What effect will it have on the working poor working in that industry, etc. We could draw up a series of 6 criteria that must be met before a tax could be considered "just." As I say: I like it.