A citizen is a citizen until death, renouncement, or if it is stripped by a court if it was obtained fraudulently. There is no requirement to ever again step foot in Canada to remain a citizen.
However ill-advised the professor’s trip to Iran was at this time, when the crap hit the fan contacting the Canadian government was a rational move. It was unlikely to pay off, but it didn’t cost much, either. And what else was he going to do in the meanwhile with Israel lobbing missiles at Iran?
I hope he gets home OK.
I agree, so do I, with his family.
Back in the day, when I was doing a lot of foreign travel (US and overseas), there were a couple of booklets freely available from racks in the international departure areas of the airport. The booklets were published by the Canadian government.
One told you about customs on your return: how much you could declare duty-free on your return, restrictions on alcohol and tobacco, prohibited items, and the like.
The other basically outlined good advice for travelling abroad. What to do if you got in trouble with the law, for example, and what the Canadian government could do for you if you did (answer: basically, recommend a local lawyer). It also contained a complete list of Canadian diplomatic missions (High Commissions, embassies, consulates) abroad, with contact information for each; and where Canada had none, what country looked after Canada’s interests there. In many cases, that was the UK, but sometimes it was the US, Australia, or Sweden.
Most importantly, though, the latter booklet explained what the Canadian government couldn’t do if you got in a jam outside of Canada.
I guess both publications are available online now, but the point is, that this kind of information is available, and should be reviewed by Canadians before they leave Canada. Especially if they’re going to a potentially dangerous place like Iran.
Airstrikes, not missiles. We had a whole thread asking why.
I’m sure that distinction matters a great deal to people whose homes have been destroyed and who may have been injured or have to bury loved ones. 
The ‘Plastic Paddy’ is a local equivalent; someone who wants the Irish passport as a matter of convenience, but otherwise isn’t interested in the country and has no intention of living there.
And what weapons were those aircraft using for their strikes?
Are there places where Canada has no diplomatic relations but the United States does?
There are some countries where Canada does not have diplomatic facilities (i.e., no embassy or consulate), especially smaller countries in Africa. They may have diplomatic relations, in the sense that Ottawa isn’t mad at them, but no resident personnel to assist Canadian travelers. For example, I don’t think Canada has anything particularly against The Gambia, but the British High Commission in Banjul is the recommended source of aid; the closest Canadian embassy is in Dakar, Senegal.
Canada and Australia have a specific agreement to share consular services in parts of the world where only one has established diplomatic facilities.
Thanks. It seemed more of an American thing to cut off diplomatic relations with countries.
BTW under the present administration, the State Department is reducing its presence in Africa.
Guided bombs (bombs with integrated guidance) and JDAMs (bombs where the guidance package is separate from the bomb) mostly.
Some missiles, I’m sure. If that’s your point.
While China is working to make friends and influence people there.
Canada did formally cut diplomatic ties with Iran back in 2012 and closed its embassy in Tehran; Iranian diplomats in Ottawa were declared personae non grata and given a few days to leave. Apparently there is (or at least was) a Canadian interests section at the Italian embassy in Iran, and an Iranian interests section at the Swiss embassy in Ottawa.
I’m not sure exactly what the situation is regarding Venezuela. The Canadian embassy there suspended operations in 2019, as apparently their diplomats could no longer obtain visas, so now the Canadian Embassy in Bogota, Colombia, provides what they describe as “extremely limited” consular services in Venezuela.
Otherwise, I think the countries where Canada does not have an embassy are where the situation is simply too unstable (e.g., Syria, Afghanistan) or just not enough need or perceived interest. For example, Canada has an “honorary consul” in Paraguay, but for emergency services Canadians need to call their embassy in Argentina, while in Tonga and other parts of Oceania the Australians provide services.