This fascinating article summarizes the argument made in a newly published book, Merger of the Century: Why Canada and America Should Become One Country.
Both make the case for a merger between the United States and Canada. It turns out that the broad outlines are, essentially, based on national security interests. Here's the dystopian opening of the article:
Imagine, if you will, a moment in the not-too-distant future: A decades-long effort by Chinese companies to infiltrate Canadian banking and drilling firms has succeeded in securing Canada's oil and natural gas fields for pillage. At least some money from these deals trickles into Ottawa's coffers, which is more than the government can say for its oil in the Arctic, where Canada has been muscled out of its claims by extraction companies with the backing of the Russian government. A network of Chinese ports has secured the sea lines along the Northwest Passage, circumscribing Canadian sovereignty, and Canada's military, enfeebled after years of reliance on the United States, is powerless to resist. Canada effectively lapses into a vassal state, reliant on neocolonial patriarchs in Beijing and Moscow.