Population and attrition.

[wausaubob]

Between 1860 and 1870 the population of the US grew at the rate of 22.22%.
But here are the growth rates for the individual states, starting with the largest state in terms of population, IL:48.86%, and MO. 45.62%, and WI, 35.93% and IA, 76.95%, and KS, 239.90%, and MN, 155.08% and MI, 58.06%, and Nebraska was admitted with a population of 122,983.
There were states in the NE that experienced population decline in the decade, such as NH and ME.
Its hard to imagine politicians in these states ever agreeing to anything that their men had conquered by force of arms, even if that was the what the eastern Yankees wanted.
Wars, possibly, are won by attrition. https://getpocket.com/explore/item/...-or-decisive-battles?utm_source=pocket-newtab

 

[JOHN42768]

You have many factors that influenced the growth. Soldiers moving around the country and found a spot they liked better even if they had never a thought of going there originally. Same soldiers getting married and raising families there. Opening of the West in general. Railroads making for easier travel. Always more births after a war. Just a few.

 

[UCVRelics]

I don't know about up north but in the South we lost over 260,000 men between the ages of 18 - 40 during the CW. There was a population decline in the first 5 year after the war, not mention the fact that a lot of older CS vets married younger women after the war which is why there were many CS widows way into the 1940's.

 

[wausaubob]

That's OK, but the process began in the 1850's. The process continued throughout the war/ https://www.jstor.org/stable/pdf/1883656.pdf See p. 272. The fact that these states had been under counted in 1860, that volunteering was heavy, and they mostly filled their quotas, made the agricultural states a place where international immigrants, easterners, and even southerners, could hide from conscription, and even start a family.