> The difference is when the US’ “brexit” moment happened the northern states decided the southern states didn’t have the right to leave and enforced their opin

> The difference is when the US’ “brexit” moment happened the northern states decided the southern states didn’t have the right to leave and enforced their opinion at the cost of 1 million lives (out of a population of about 32M at the time). An interesting analogy, but it downplays two key differences. Firstly, the confederate states opened fire on union troops, whereas Britain did not start a shooting war when it left the EU. Secondly, there is no provision in the constitution of the United States for a state to leave the union, unlike in the EU. As a final point, I would note that the United States of America by that point had a history of using military force to expand (in line with Thomas Jefferson's "empire of liberty" doctrine), including two attempted invasions of Canada, the Mexican-American War, as well as successful wars (and massacres) against the Native peoples. So if you do take the position that the confederacy had the right to secede from the United States, it is hardly a surprise that the USA then took the opportunity to use military force to annex a smaller neighboring nation with a weaker military, limited infrastructure, and insufficient foreign support to defend itself.