Actually, I have time, so let's dismantle your comment.

"Keeping thieves and robbers from entering your house is not, 'immobilizing yourself.' "

Nobody said it is.

"The idea that America would be immobilized by taking care of itself instead of carousing around with the rest of the world is just silly."

Something nobody said again, but:

Thinking that having literally enough land to fit people and resources to perpetuate some contemporary level of technology ignores all of history and every metric of national success.

You know who had overabundant physical resources and separated themselves from other civilizations?

Incans.

"Canada could also seal off its borders and in a thousand years from now still be going strong."

So we ignore Canada's transportation imports, machinery imports, electronics imports, plastics imports, energy imports， services that alone account for 1/3 of Canadian GDP, then Canada will "go strong"?

5 winter months a year without cars, oil or modern manufacturing to compensate for the weather, not to mention financial services, infrastructure services, science in every form; they're sunk.

Oh and we can't forget that you are wishing away Canadian exports, which also account for 1/3 of Canadian GDP.

Your canadian isolationist whim has zero legs to stand on and 1.5 trillion dollars of debt annually.

"International relations are the cause of war" in the same way that air is slowly poisoning you to death.

Such a zoomed-out, irrelevant statement ignores literally every significant factor of conscious reality.

There are two hundred ish countries.

Show me the thriving utopias that refuse to interact with any other countries.