Shane, I'm not so sure that the efforts of Forrest helped lengthen the
war by a year or more, but he did tie up a lot of troops for a while.
Charlie, Semmes did do a lot of damage to shipping, but only managed
to put a dent into foreign shipping into the US, and did nothing to affect the shipping of foodstuffs from the US to Europe, even though there was a drop off in the last 2 years, which was caused by not Semmes, but better growing seasons in England and France.
Before going any further, I will say that I find both Forrest and Semmes to be extremely interesting people from the CW. I've read several books on Forrest and have a couple on Semmes and the Alabama that I'm trying to find time to read.
However, the question is between Semmes and Mosby.
Why not Mosby instead of Semmes. Mosby appears to have kept a lot more military tied up trying to control/or put him out of commission than Semmes.
Will admit that I haven't read much on Mosby and not really sure if he was that big a nuisance to the Union forces in his area of operations.
Only going on what I have heard and read.
Chuck in Il.