So, when asked about dual citizenship, I’ve been pretty vague in saying that the US seems to only really care about my US citizenship.
The US State Department offers a bit of guidance here, which I found a bit surprising and even more vague, specificially:
However, a person who acquires a foreign citizenship by applying for it may lose U.S. citizenship. In order to lose U.S. citizenship, the law requires that the person must apply for the foreign citizenship voluntarily, by free choice, and with the intention to give up U.S. citizenship.
Intent can be shown by the person’s statements or conduct.The U.S. Government recognizes that dual nationality exists but does not encourage it as a matter of policy because of the problems it may cause
So, I read more and I asked around… and here’s what I gather:
The only rule the US has on dual citizenship is that you must always enter and exit the US on your US passport. You must carry both when travelling and use the fast line for citizens upon arrival in each respective country.
You must always take both passports because the US Government fines airlines around $3,000 if they board an American citizen traveling on a foreign passport. I expect this must happen quite frequently.
Also, when renewing my US Passport, I must include a very brief letter along with the application stating something along the lines of: “I Francoise, chose to naturalize as a UK citizen in 2011. At no time did I intend to relinquish my American citizenship, nor do I intend to do so in the future.” The reason for this, is that taking on a foreign nationality is a potentially expatriating act (as mentioned in the text above), but the Supreme Court has ruled that you only lose your American citizenship if you expressly intended to do so when taking on the other nationality. It seems that as long as one makes it clear that that one wanted both, and not simply to take on UK citizenship while rejecting US citizenship, all is fine. While the idea is implicit in the sense one would be renewing a US Passport, you still need to state it explicitly.