Okay, I've been actually getting a few messages/emails/comments about this lately, so perhaps it's time for a new topic.
One of my earlier posts commented on the difficulty of a Canadian like myself obtaining dual US-Canadian citizenship. Since then, many have tried to tell me "No Mike, you absolutely can obtain dual citizenship." And thus refer me to some website or another, or relate tales of some friend or another.
There is the rare reference that at least implies that US naturalization into dual citizenship is perfectly valid. For example, straight from a .gov, "A U.S. citizen may acquire foreign citizenship by marriage, or a person naturalized as a U.S. citizen may not lose the citizenship of the country of birth". Encouraging. Another link, with some interesting references and details.
The law itself say practically nothing on the subject, leaving it to case law, USCIS rules and memos, and in the end, the whim of those who may oppose you. The primary factor that makes these things different are "renunciation oaths", requiring you to pledge to give up your previous citizenships. Canada used to have such an oath, but it was made illegal in 1973 by the courts and removed. The US renunciation oath remains. However, an mportant point - most countries in modern times, including the US and Canada, simply ignore foreign oaths of this sort. Basically, this means, from a country's perspective, they don't lose you as a citizen, regardless of what you said, until you march into an embasy office and tell the government directly (and probably fill in a million forms).
However, I found this link to be the most telling resource, citing cases and giving many many FAQs, including one or two with details on this specific case. Here is what I found to be the most telling quote:
"Finally, some people who become US citizens hope to take advantage of the fact that the US didn't make them actually go to their old country's consulate and get their citizenship revoked (all they were required to do was make a renunciatory statement as part of the US naturalization oath) -- and so they continue to exercise rights of citizenship in the old country as though nothing had happened. The US State Department used to take a dim view of such behavior if they found out about it, and people acting in this way were known to lose their US citizenship on the grounds that their pledge to renounce their prior status had evidently not been made in good faith. Now, though, the State Department almost never pursues such cases."
So, in the end, we're right back where I said we were when I wrote my first post on the subject (see? I'm not TOTALLY stupid) - it's against the oath, but not any explicit law. However, wee now know that such oaths carry little weight in practice, and that after 1990, the US has done very little to enforce them.
Of course, this still does not answer the question: if I could have it, would I really want it?