David S Poepoe said:
Dropping Lincoln from the equation. I think the westward expansion of the US would be slightly slower, there wouldn't be all those men at arms. On the whole I doubt the US would take to warring against Britain, it would probably be mostly still isolationalists. I think Spain would top the list of most likely targets. It would be an easy kill to start learning from.
I don't agree with the idea that the western expansion would be slower, it had already started, (Oregon 1854, California 1849, etc) and once the transcontinental railway was in, it is a fiat accompli, and nothing was going to stop the westward expansion of the railroad.
I also believe that if the US purchases Russian Alaska, the war with Great Britain is almost inevitable, It would be important to "connect this great republic, undivided and free."
I think the reasons are twofold. First, with no Civil War you have greater population pressure. Western and Central Europe continue to supply Eastern Factories, Mines and Mills, and you have a great agricultural migration pouring from Europe into the free lands of America.
Second, Europe in general, and Great Britain in particular, do not understand the substantive difference in the quality of the officer corps caused by the acadamies of West Point and Anapolis. They will not understand that the USA as a world power (Hell it took the USA 50 years after 1860 to realize exactly how strong they were.)
Third, the centralization of power into Washington would have occurred anyway, it is only founded in part on the ACW. In fact the roots of this inevitable centralization of power are found in Marbury v. Madison, long before the ACW. The ACW accelerated the centralization, but didn't cause it. Nothing like a war with Good ol' England to get us all pulling together.