But is there a limit to a modern state’s power to tax? The conventional answer is, “probably not” — as long as government does not flagrantly discriminate, its power to tax is extensive. Yet in one aspect the United States has expanded the power far beyond limits fixed by other nations, and the question of whether it has violated international law in doing so should be raised.

Let us consider the hypothetical case of a person born in France of American and French parents. He grew up in Paris where he began his working life; he has never visited the United States and does not have a U.S. passport. He has never attempted to derive benefits from the U.S. government. For all intents and purposes he is only a French national, save that his mother registered him at the U.S. Consulate when he was born (although he would have American nationality even if she had not).

He now earns a substantial amount of money and pays French taxes, but he does not file a U.S. income tax return. The Internal Revenue Service discovers his existence and asks him to file a tax return. He refuses. The I.R.S. then assesses a huge income tax on him and invokes the cooperation provisions of the U.S.-France double taxation treaty. Those provisions require the French government to assist the United States in collecting its taxes.

The man responds by suing the French government. He claims that the attempt to take his property by hanging the power to tax on the single thread of his involuntarily acquired citizenship violates the First Protocol of the European Convention on Human Rights. This states: “No one shall be deprived of his possessions except in the public interest and subject to ... the general principles of international law.”

The man tells the court that it is not in the public interest to tax solely on the basis of citizenship. He says he has no contact with the United States, that he acquired American citizenship involuntarily and that he cannot give it up without first paying the taxes that he is contesting.

Basing the power to tax on citizenship alone, he tells the court, violates customary international law, as shown by the fact that no other first-world country taxes on the basis of citizenship. Indeed only one other nation out of the world’s 194 states does so. The remaining 192 impose an income tax only on those who reside within their territory or on those whose income is derived from within their territory.

While an increasing number of Americans living abroad are trying to give up their citizenship, the U.S. government makes it difficult to do so.

In the first half of the 20th century the United States regularly expatriated citizens who did not want to give up their nationality. But later in the 20th century it shifted to the other extreme: it made it very hard to do so.

A person can only give up American citizenship before a consular officer. He must fill out a ream of papers and answer many questions. Finally, his attempt to shed his nationality will only succeed if he can show that he has paid U.S. taxes. Only then will he receive a loss-of-citizenship certificate confirming that he is no longer subject to U.S. taxes.

So, to get back to our hypothetical French-American, the French courts presumably would be bound by the terms of the French-American double taxation treaty to assist the I.R.S. in collecting the tax that it imposed on him.

But how would the European Court of Human Rights in Strasbourg rule? The answer to that question awaits a brave American citizen willing to file a test case while aware of the risk that he could become a sacrificial lamb.

Ronald Sokolis an attorney qualified to practice law in the United States and France. He is the author of “Justice After Darwin,” “Federal Habeas Corpus” and other books and articles, and lectures annually on “What is Justice” at Imperial College, London.