VANCOUVER — Their position on marijuana is hardly the only difference between Canada’s prime minister and the president-elect of the United States.

But when Justin Trudeau’s government introduces legislation to legalize cannabis this spring, it could spark problems between Canada and the U.S., particularly since Donald Trump has indicated he will keep pot illegal at the federal level.

Here’s a look at what could change in Canada-U.S. relations once Canadians start lighting up legally.

Border control

Len Saunders, an immigration lawyer in Blaine, Wash., predicts a boom in his business after Canada legalizes marijuana — though it’s one he has a hard time feeling happy about.

Saunders represents Canadians who have been banned from entering the U.S. after admitting they have smoked marijuana in the past. Every year, he files as many as 30 costly waivers for people who’ve made this admission and hope to regain access. [Read more at Huffington Post]