Like he originally said during the maralago dinner with Trudeau, the tariffs are moreso about "border security", meaning militarization, metering, and holding cells on either side (Mexico is already considering to hold non-mexican deportees in their facilities). And if they don't play ball, it's tariff time baby.

It was conveyed to the Canadian delegation the tariffs are unavoidable in the immediacy, but solutions in the longer term are on the table, particularly if the border is better secured.

I'm a big believer in tariffs. I think tariffs are the most beautiful word. I think they're beautiful. It's going to make us rich

Trump said in an interview with NBC's Meet The Press that aired Sunday. In that interview, the U.S. president-elect later reiterated his border concerns:

We can't have open borders. And I said to the president of Mexico and to Justin Trudeau, if it doesn't stop, I'm going to put tariffs on your country at about 25 per cent

https://www.cp24.com/news/canada/2024/12/10/trump-refers-to-prime-minister-as-governor-justin-trudeau-after-saying-canada-will-respond-to-tariff-threat/