Because 1) the question is why the US - unlike every other country except Eritrea - has this policy, 2) it&#x27;s difficult or at least expensive to renounce citizenship, and 3) it&#x27;s only been in the last 10 years or so that many Americans have even heard of this requirement.<p>As you can read in this thread, it costs over $2,000 to file renunciation, and your taxes need to be in order. Resolving the tax situation in this case sounds quite expensive. Oh, and I think you have to pay taxes for up to 10 years after renunciation, and you can&#x27;t renounce until you&#x27;re 18 years old.<p>Suppose you were born in the US while your British parents were finishing up a college education. You left the US when you were 6 months old. You&#x27;ve not back to the US, you have no US relatives, you don&#x27;t know anything about US taxes, or Selective Service requirements, or other obligations of US citizens, and have no plans to even visit the US. Then at the age of 40 you realize that you are under US law. You want to renounce citizenship, but learn you&#x27;ll need to pay $150K in penalties, even though you&#x27;ve been paying UK taxes all your life and would never have needed to pay US taxes had you filed. You only have $50K in savings.<p>What do you do, and how do you think you would feel?