It used to be pretty easy for Canadians to work in the US, almost a casual thing. Partly because in the old days no one checked and Canadians could easily blend in as Americans. Partly because before the sixties I believe they had preference for visas.
I would be in favor of some kind of agreement allowing US and Canadian citizens to work back and forth across the border. It needs to be reciprocal. I wouldn't mind seeing a similar, reciprocal, agreement with the Aussies for that matter.
I would not be in favor of allowing the same agreement with Mexico. Canada and the US are pretty similar; Mexico is not. But Canada would need to tighten up their immigration policies so that they don't become simply a bridge bringing people into the US that wouldn't otherwise be admitted. Heck, we need to tighten up our own immigration policies.
Unfortunately, I think the point of this is bringing down the border with Mexico; if we eliminated Mexico from the agreement the CFR and the political class probably wouldn't be interested.
I like Mexico, but it is too dissimilar to be allowed into such an agreement.
In Canada you can’t work for more than 5 years as an American. Here we’ve taken in Canadians for years...who work in companies for years...even retiring with them...seems the U.S. could at least tighten that up a bit.