I don't understand why this debate is going on.
Forget the politics.
Canada is the USA's best friend, not the UK or any other country.
Just look at the map.
Canada is by far the United States' largest trading partner, with more than $1.4 billion in trade per day.
Canada supplies 16.5 per cent of all US imports of goods and services, while Canada bought 19 per cent of all American goods and services. That's a lot.
Canada is the leading export market for 35 of 50 U.S. States like New York and Michigan, so lots of jobs in the US depend on Canada.
Also, Canada has a lot of oil, and it's ready to flow to the US.
Finally, Canada and the US signed an agreement, it's called NAFTA and it vowed to encourage free circulation of goods AND persons in North America.
Under this agreement, qualified Canadian professionnals can obtain a TN visa to work for one year in the US, and it's renewable
The deal is reciprocal: remember that Americans too can get into Canadian programs in general. (I know med schools that train a lot of Americans... and the tuition is much cheaper in Canada...)
If Canadians get into US programs, it's because they are more qualified. (Remember that dental school is much harder to get into in Canada)
And if a program has to choose between a qualified American and a Canadian, I can bet you they will take the American.