The 17thA was 1913, and a lot of damage to the Republic occurred around that year, like the creation of the FED.
I’d argue that the death knell can be traced earlier than that.
E.g., the Act of 1871 and the incorporation of the District of Columbia.
You are so correct..
The Act of 1871 was repealed in 1874, Congress replaced the District’s quasi-elected territorial government with an appointed three-member Board of Commissioners. Direct rule by Congress continued until the 1973 passage of the District of Columbia Home Rule Act, a century later. Signed by Nixon somehow he was convinced this increase black support for the GOP.