But what would the LTCG be on those assets? At most $2m * 15% = 300k (assuming you were able to realize it over several years and avoid the 20% LTCG bracket and

But what would the LTCG be on those assets? At most $2m * 15% = 300k (assuming you were able to realize it over several years and avoid the 20% LTCG bracket and 3.8% NIIT), cheaper to pay the taxes than buy a passport and you would preserve your ability to return to the US if you found it in your interest.