Ulysses Grant served from 1869-1877 so he was President when the Constitution was changed in 1871 for the present corporate Constitution that has enabled everything that Mr. Boutwell "prophesied". In other words he may have been privy to the designs of the powerful to do exactly what he predicted.
It is also the case that the accretion of power to the centre had already been achieved with the victory of the centripetal forces in the Civil War and the passing of the 14th. Amendment in 1868.
It may be that he witnessed these events and their aftermath from an insider's perspective and followed their implications logically to their conclusion. Or it may be that he was, as I suggested, privy to the plans of the powerful men who even then controlled the destiny of the nation.
"Jesus answered them: 'Truly, truly, I say to you, everyone who commits sin is a slave to sin. The slave does not remain in the house forever; the son remains forever. So if the Son sets you free, you will be free indeed.'" (John 8:34-36)
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