I'm always critical of how important America is in history. Makes me feel kinda bad, now and again.
Anyway...I argued in another thread that America's presence in the First World War might have made the Versailles peace ineffective - or, alternatively, it provided the force that made it just potent enough to incite German irredentism.
That aside, let's say that the second world war does happen, and that the CSA survived the ACW.
First, it may or may not be likely that America does not become an industrial superpower such as it did. In the case that it still does, the US is likely still to supply Britain, just as the CSA is. Even if the CSA doesn't, it's extremely unlikely to be able to supply the Germans, courtesy of the Royal Navy.
Second. If the North is not the industrial power that it was historically, the industrial vacuum would have encouraged the creation of industry elsewhere - likely in Britain and France. The US and CSA are likely to become client states of the industrial powers - effective dominions for commodity export. Alternatively, the USA still does become an industrial power. The CSA is unlikely to, especially as long as it keeps cotton as its staple.
Speaking of cotton, the CSA's cotton exports are likely to tie its foreign policy with Great Britain's so much as the USA's is. Even after cotton becomes less of a concern, Britain - as a world power - is likely to continue to try and be a close friend of the CSA. Amid the rise of Germany, Britain is obliged to search for allies wherever she may find them, possibly even in a conciliatory policy toward both American states. With her economic strength and the strong, long-standing economic bond between Britain and the two American republics, Britain is likely to be a friend more than a rising Germany.
Alright. So, there are several alternatives. If American industry is shipped out to an already industrialized state in the de-industrialization scenario, it is more likely to go to Britain, France, or Japan, who are more likely to use the raw materials that America exports, such as cotton. In the case that it goes to Japan, Britain is more likely to make a conciliatory policy that keeps Japan in her circle, possibly even using Japan as leverage against the American republics to keep them in her sphere against Germany.
In the war, the two republics are economically likely to ship goods to Britain simply because it would be very difficult to ship them to Germany, not to mention the long-standing economic bond between the two. If American industry remains in America, then America will still support the British with her industrial strength regardless of whether she joins. If American industry is shipped out to Japan, France, or Britain, it is likely to strengthen the allied side. If it is shipped to France or Britain, it could likely strengthen them enough early on to prevent the early occupation of France and the Low Countries.
After 1941, when the Americans joined the war, the British had already beat the German air force, bottled the navy, and pinned the army. The Soviets had stopped the Wehrmacht in its tracks. The likelihood of Japan's satisfaction in the Pacific - with the lack of a great American presence there - increases her ability to side with London in a war, as she had in the war. Although it is possible that she may endeavour into the Soviet Union on the Germans' side, I find it more likely that Japan would go into China as she did historically, and focus there where expansion would be easiest, and possibly more profitable. The British would benefit by not having to fight in Burma or the Pacific, and having only to devote forces to North Africa and Europe.
