The US used to require new citizens to renounce other nationalities, and I haven’t heard of them changing this. Rupert Murdoch had to renounce his Australian citizenship when he became a US citizen in the 80s. I think Linus was naturalised in the 90s or 00s, so not too long after.
How Do You Get Dual Nationality?
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Naturalizing as a U.S. citizen while keeping the nationality of another country.
Wikipedia says:
Since 1990, the State Department has allowed multiple nationalities.[130] Official policy is one of recognition that such a status exists, but the U.S. government does not endorse a policy of having multiple nationalities, though it is permitted.[151]
The US used to require new citizens to renounce other nationalities, and I haven’t heard of them changing this. Rupert Murdoch had to renounce his Australian citizenship when he became a US citizen in the 80s. I think Linus was naturalised in the 90s or 00s, so not too long after.
https://travel.state.gov/content/travel/en/international-travel/before-you-go/travelers-with-special-considerations/Dual-Nationality-Travelers.html says that dual citizenship is allowed. From that page:
Wikipedia says:
https://en.wikipedia.org/wiki/United_States_nationality_law#Dual_nationality