The conviction and subsequent seven-year sentence handed to Egyptian-Canadian Mohamed Fahmy in an Egyptian court on terrorism-related charges highlights the complications individuals who hold dual citizenship may face if they run into trouble in their country of origin.

"The reality is when people do hold multiple citizenships, it can make it more complicated for Canada to intervene," said Sharry Aiken, an associate law professor at Queen’s University.

​​"But that's on an operational level. It's not because there's something in law that says that should be the case. It's an operational thing. It's a policy thing."

Canadian officials had warned the family of Fahmy that the journalist's dual citizenship placed limits on how much they could do (although the government has also said that Canada has been granted full access to Fahmy to provide consular assistance).

Foreign Affairs Minister John Baird had told the Globe and Mail in April that "many countries put up road blocks" when it comes to dual citizens and that they won't recognize the other citizenship.

'He's our citizen'

​​"What the government of Canada does say about dual citizenship is that if you are a dual citizen and you are travelling in the country of your other citizenship, it may be more difficult for Canada to extend to you meaningful consular assistance and diplomatic protection," said Audrey Macklin, a professor and chair of human rights law at the University of Toronto. "Why? Because the other country may say, 'Butt out, he's our citizen."

Although it's unclear what passport Fahmy used to enter Egypt, his brother told Global News earlier this year that the family have been travelling back and forth on Canadian passports for decades. Fahmy, the acting Cairo bureau chief of Al-Jazeera English, along with two other journalists, were arrested in December in Cairo, accused of supporting the Muslim Brotherhood, which the authorities have declared a terrorist organization.

But Aiken said the Canadian government should advocate on any dual citizen's behalf with as much vigour as they would any other Canadian, regardless of what passport they use to enter a country, or however many citizenships they may have.  

Toronto immigration lawyer Michael Niren said that the country that also has claim to the citizen might act more aggressively against that person than they would someone who is just a Canadian citizen.

"Let's say you're an Egyptian citizen as well as a Canadian citizen. The authorities would probably be emboldened to take more aggressive action because you're subject to laws of that country as a citizen."

When it comes to international law and the treatment of dual nationals, some countries have signed on to a 1930 Hague convention. That treaty states that a state "may not afford diplomatic protection to one of its nationals against a state whose nationality such person also possesses." 

"It's not a treaty that obliges the government to provide protection," said ​Macklin. "It's simply one that says in these circumstances if you sign this treaty you are saying you won't [provide protection] when the person is in the country of their other nationality."

But Canada is not a signatory to that treaty.

Dual citizenship not always recognized

As well, unlike Canada, many countries, in particular non-G8 countries, do not recognize dual citizenship. Canada doesn't require an individual to give up any citizenship of another country. But whether that person's country of origin recognizes their dual citizenship is a question from country to country, Niren said.

Some applicants will have to give up their home citizenship because they're not going to be recognized anymore. For example, many Chinese nationals coming to Canada must give up their Chinese citizenship, as China doesn't recognize dual citizenship.

A government of Canada website also cautions Canadians who have dual citizenship that it "may not be legal in the country of your second nationality, which could result in serious difficulties.

"You may have outstanding obligations in the second country, such as military service or taxes. Dual citizenship can also cause problems in a third country if there is confusion over which citizenship you used to gain entry," the website says. It advises people to contact the appropriate foreign government office in Canada before heading abroad.

Some countries may also feel more justified on their claim on a dual citizen who has gotten in trouble with the law if that person used that country's passport to enter.

An easy solution for Canadians would seem to be to always use their Canadian passport.

But "some countries take the position that they don't mind if you're a dual citizen, we don't care, but when you're coming into our country, you use your passport from this country," Macklin said.