The key is to look at the current budget: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;2015_United_States_federal_budget#Outlays_by_budget_function" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;2015_United_States_federal_bud...</a><p>It can be split into three families of spending:<p>- defense, which benefits you globally via Pax Americana, free trade routes etc. and should you require it, &quot;Captain Phillips&quot; style rescue.<p>- &quot;socialism&quot;, in the form of benefits that everybody has to pay for and that you can receive if you trigger certain situations (retirement, unemployment, etc.). Most expatriated Americans probably already benefitted from free education which is included here.<p>- &quot;generally making the country locally better&quot; (justice, environment, etc.).<p>Of these, only the latter doesn&#x27;t directly impact Americans abroad. The first benefits you wherever you are; foreign citizen somewhat benefit from Pax Americana but there is no guarantee it will continue, whilst US citizen are covered globally with much more certainty. The second is a form of compulsory insurance for life developments that will probably coincide with repatriation. But that&#x27;s about 7% of the budget (rough back of the envelope).<p>The question is why don&#x27;t other countries tax their citizen abroad? I think it is mainly because they can&#x27;t afford to enforce it (good luck, Estonia, forcing JP Morgan to give you access to their New York client data). If they could, with any degree of certainty, they would in a heartbeat. France proposes to do it every 6 months.