Which countries intervened in the American Civil War?

Britain and France intervened in the American Civil War.

At the beginning of the war, the strength of the north greatly surpassed that of the south. The population of 23 northern states is 22.34 million, while that of 7 southern states is only 965.438 million, of which more than 3.8 million are slaves. The industry in the north is developed, the railway network extends in all directions, and food is abundant. There is almost no industry and few railways in the south. However, the south is well prepared militarily, its army is of high quality, its arms industry is developed and it has received assistance from Britain and France. In addition, on the eve of the civil war, President Buchanan (the agent of slave owners) tried to transport a lot of weapons and money to the south. The south wants to defeat the north by making a quick decision.