Regarding Port-of-Entry examinations (not regulations governing commercial transportation for example, like requirements to possess and present specific types of documents to obtain approval to board an international commercial airline flight)
for persons with both U.S. and Canadian citizenship:
Overall:
U.S. border officials expect U.S. citizens to identify themselves as U.S. citizens and accordingly present documentation showing their U.S. citizenship (typically a U.S. passport but for land travel across the U.S. border, for example, there are alternative documents, such as some states' enhanced drivers licenses, that will suffice). Likewise for Canadian citizens arriving at a Port-of-Entry (PoE) into Canada, border officials expect Canadians to accordingly present documentation as to their Canadian status (for citizens, their passport but with similar allowances for some alternative identification documents when traveling by land).
Thus, depending on the individual's planned or anticipated travel, a passport might not be necessary since some travel between the U.S. and Canada can be adequately facilitated by having other forms of enhanced identification. I am not sure what the eligibility requirements are for the various versions of enhanced identification, except the obvious: to have a particular U.S. state's enhanced drivers' license, for example, of course the individual needs to be a resident of that state.
The best approach is to simply have a passport from both countries. Both issue ten year passports now, so this is not a particularly onerous burden for those who travel internationally. This allows an individual the most flexibility and will accommodate international travel generally by all modes of transportation. (That is, including meeting regulations governing commercial transportation.)
But again, depending on the individual's planned or anticipated travel, enhanced identification for the country in which they reside and a passport from the other country could easily meet an individual's needs if they are only traveling between the U.S. and Canada.
BEYOND THAT (beyond the general expectation of officials that individual's who are citizens of that country identify themselves as a citizen and present documentation accordingly)
:
Experience and anecdotal reporting tends to indicate, for individuals who are both a U.S. and a Canadian citizen, the U.S. is typically more strict in PoE examinations than Canada. That does not mean there is a fine or other penalty for failing to present a U.S. passport when applying for entry into the U.S.
UNLESS there is some other particular grounds for imposing a penalty . . . like making misrepresentations.
Some key reminders are relevant here:
-- just showing up at the PoE constitutes making an application to enter . . . this is true for both Canada and the U.S.
-- misrepresentation by omission is a real thing, so presenting a Canadian passport (and not a U.S. passport) to the border official in the PIL (Primary Inspection Line) at the PoE when applying for entry into the U.S. could be construed to be a misrepresentation as to nationality for an individual who is a U.S. citizen
The latter demands further explanation. Remember,
the law in both the U.S. and Canada does not formally or officially recognize dual citizenship. Having more than one citizenship is not prohibited by either the U.S. or Canadian law. And both governments, and in particular those who work in border control and immigration, respectively, are well aware that many individuals have multiple citizenships, meaning citizenship in more than one country. Online information posted by the Canadian government sometimes even refers to "
dual citizens," referring to individuals who have citizenship in at least two countries (some have citizenship in more than two countries). This is mostly a nod to the common nomenclature, using language most people readily understand,
but in the law itself there is no such thing as a "dual citizen" (again, referring to U.S. and Canadian law; other countries may officially recognize dual citizenship).
Generally travelers are required to disclose their "
nationality" when making an application to enter the U.S. or Canada. How specifically this is asked seems to vary, but appears to vary more so at the Canadian PoE than a U.S. PoE. That is, the U.S. tends to be far more consistent in asking a direct question about the traveler's nationality or citizenship. This is where the formalities of the law, and the fact that "
dual citizenship" is not recognized in the law, kicks in. The U.S. does not recognize citizenship in any other country than the U.S. if the individual is a U.S. citizen. And yep, some U.S. border officials can be downright authoritarian in how they interpret and apply this.
If a U.S. citizen presents a Canadian passport, for example, when asked to show documentation (language used in the question varies), that can be understood to be deceptive, a misrepresentation as to nationality, remembering the U.S. border official (generally) will not formally recognize the traveler is a Canadian citizen. So it will generally be better if the traveler responds saying something like "
I am a U.S. citizen but I do not have a U.S. passport" and then offers alternative identification, which could be their Canadian passport, BUT probably better to show some other form of identification first and a Canadian passport only if asked.
NOT a good idea to tell the official "I am also a Canadian citizen" (unless asked a question for which this is the appropriate response), because, again, so far as the U.S. law is concerned, which is what the U.S. border official is applying, if you are a U.S. citizen, the U.S. law does not recognize you are also a Canadian citizen (note, for example, for a Canadian citizen who is also a U.S. citizen and who is detained in the U.S., the authorities there do not need to give the Canadian access to the Canadian consulate, since again the U.S. does not recognize that a U.S. citizen also has Canadian citizenship).
Technically it is very much the same coming into Canada EXCEPT, again, experience and anecdotal reporting suggests that it is unusual for Canadian border officials to make an issue of this. In fact, so far as I have seen, it is rare for Canadian PoE officials to make an issue of it when a Canadian citizen presents a U.S. passport.
Been there, going both ways, and seen the difference. And what I saw was fairly consistent with anecdotal reporting. And consistent with the law, albeit much more strictly interpreted and applied by the U.S. (so it seems) than Canada.
Final Observation: also seen, and it too was consistent with anecdotal reporting, that travelers upfront with U.S. border officials about being a U.S. citizen but not in possession of a U.S. passport (or alternative enhanced identification), not encountering one of the more authoritarian U.S. officials, are typically and politely admonished to get and have a U.S. passport the next time.
