President Trump just said “Canada should become our Cherished 51st State.” Looking back on history, how might such a thing happen? What past examples are there of nations “annexing” or “absorbing” reluctant neighbours whose population is 10% of theirs? And how did that work out?

Have there been of examples in history where one bigger group uses economic force to coerce a smaller nation or group (but still not that small, constituting 10% of the population of the bigger nation) to join them and become members of their nation?

How have things turned out in that example?

The question is deliberately vague to allow more answers from across time, but perhaps narrowing our timeline to the mid-1800s to the First World War might be relevant because that appears to be the time of the "Golden Age" the current American President wants to emulate...