Boris would have to follow the appropriate procedures for "expatriation", as the process is called. Even after formal renunciation of citizenship, the former citizen can still be subject to US taxes (this is written in his passport). In order to terminate this, he needs to file expatriation form 8854 to the IRS. If his net worth is more than $2 million or his average income over the previous five years has been over $124,000, he is assumed to have renounced his citizenship for tax avoidance and has to pay Expatriation Tax. He also needs to show he has paid all his US taxes for the previous five years. In that case he can visit the US, but even so if he stays longer than 30 days he will have to pay US taxes for the entire year. See here for more details. If at this stage it is discovered that he didn't pay taxes in the past, he could get into trouble.Christophe wrote:I don't think that's true, is it? Plenty of people have renounced US citizenship to take on another citizenship in cases where their new country demands it, for example, and they are not denied entry to the US subsequently, although of course they must travel there as aliens and have no special rights there. People who renounce US citizenship in order to try to avoid tax or other obligations or in an attempt to avoid prosecution under the law might be treated differently in practice, but Boris J wouldn't fall into that category.Marco 72 wrote:[In that case however he will probably be denied entry to the US for the rest of his life.
Some US citizens willingly choose to disregard these rules and just don't file taxes. This can be risky however, since tax evasion is a federal crime with stiff sentences (see Al Capone's case) and is not covered by the statute of limitations.