What would have happened if the Confederate States of America had won?

In my opinion, the impacts of such an outcome on world history would have been tremendous.

Most people would think of the continuation of slavery as the major impact.  I don't think so.  I think that slavery would have died relatively soon (perhaps, like Brazil's, in the 1880s) because of economic pressures.

What would have been really important, I think, is that the US would never have become a superpower.  This is because the US would not have been this monolithic country, pretty much impervious to invasion.

Imagine, instead, the CSA siding with England in WWI while the USA sided with Germany.  It seems likely that the two countries would have taken different sides in that and any other war.

It's hard to imagine what the ultimate outcome would have been.  Maybe Britain would have remained as the major superpower without the US to challenge it.

At any rate, I don't see how the US (or the CSA) could have become a superpower in such a situation because each would have been too vulnerable to attack from the other.