User blog comment:Frymon/Ideas for my Timeline needed/@comment-461469-20100812015815

Napoleon III, Emperor of France at the time, wanted to recognize the Confederacy in order to try to succeed in his attempt to install a puppet monarchy in Mexico, under Maximilian of the Hapsburg family. He only failed because the civil war ended, and the US put the Monroe Doctrine into affect, and Napoleon withdrew from Mexico. So, France would most likely support the South, while Britain may just go along with it, but their wouldn't be a Mexican-Confederate War because of Napoleon III's puppet in charge, which would destroy the CSA's only major ally unless it happened after 1871, after the Franco-Prussian war, which ended in French defeat.

So, I would say if Britain and France supported the CSA, then the US would be forced to give up from the threat of the destruction of the US Navy blockade of Southern ports, and invasion from Canada.

There.