Canada

We can see from their Russian masters how an American invasion would take.

They’d try to grab and hold strategic areas and resources, while using missiles and aircraft to cripple the economy and infrastructure and spread fear nationwide.

However, we can remember that the US has tried to invade many other countries and they’ve failed every time. And while we may never have the tanks and aircraft to match them in open warfare, even much poorer countries than Canada were able to successfully repel the American forces.

And in this scenario we’d have a massive untamed border to use to make counter strikes, and would likely get significant military support from allies around the world and in the US as well.

So it would be monumentally devastating on both sides. It would be a catastrophically stupid endeavour. Which doesn’t rule it out, they have extremely stupid people in charge.

But personally I believe the US would descend into civil war before this happens, with “blue” states having suppressed voting rights trying to secede.