The Supreme Court of Canada has ruled that expats have the right to vote in federal elections no matter how long they have lived outside the country.

In a 5-2 decision, a majority of justices said the infringement to charter rights is not justified.

Writing for the majority, chief justice Richard Wagner said voting is a "fundamental political right, and the right to vote is a core tenet of our democracy."

"Any limit on the right to vote must be carefully scrutinized and cannot be tolerated without a compelling justification," the judgment reads.

The Liberal government already passed legislation last month that guaranteed voting rights to all Canadians residing outside the country, but Friday's ruling could have the effect of preventing future governments from enacting legislation to limit voting rights for citizens living abroad.

Previous legislation enacted in 1993 barred non-residents from voting if they lived outside the country for more than five years. It was loosely enforced until the Conservative government of Stephen Harper, triggering a charter challenge by two Canadians living in the U.S. who were barred from voting in the 2011 election.

Gillian Frank and Jamie Duong, who worked at American universities because they could not find work in Canada, said they maintained deep ties to the country despite their residence abroad.

The judgment highlighted the global nature of modern society, and says that denying voting rights to non-resident citizens simply because they have crossed an "arbitrary" five-year threshold "does not stand scrutiny."

'Every citizen counts'

Under Bill 76, which amends the Canada Elections Act and passed in December, voters residing in other countries must only prove their identity and show proof of their previous address to determine the riding in which their ballot would be cast.

Colin Feasby, a lawyer for the Canadian Expat Association which intervened in the case, said the decision makes an important statement that "every citizen counts."

"The majority explained that we live in a community defined by citizenship, not residency and that Canadians who live abroad are just as Canadian as those who live in Canada," he said.

"The majority also rejected the philosophical 'social contract' argument advanced by the attorney general to limit voting rights and made it clear that a compelling justification presumably supported by evidence will be required to limit important charter rights in the future."

The attorney general of Canada had argued Parliament's decision to limit voting for long-term non-residents is "a demonstrably justified infringement of the charter right to vote," and that a social contract exists between electors and lawmakers.

"One of its purposes was to maintain the fairness of the electoral system to the resident Canadian," reads a legal factum filed with the Supreme Court. "The legal responsibilities of long-term non-resident citizens under Canadian domestic law are much less than the responsibilities of resident Canadians."

Expat advocates argued before the Supreme Court that the right to vote is guaranteed under the Canadian Charter of Rights and Freedoms, is central to Canadian democracy and is a defining characteristic of Canadian citizenship. Denying them a vote was akin to treating them as second-class citizens, they argued.

Civil liberties advocates also welcomed the decision.

"The decision reinforces the right to vote as a fundamental right and the cornerstone of democracy — not something that Canadians must earn from the government," said Kate Oja, a lawyer with the British Columbia Civil Liberties Association, in a statement.