I disagree, the destruction started with the 17th Amendment and the beginnings of Progressive Liberal Politics in the late 19th Century. Culminating in the FDR being elected in 1932, there is your demarcation point when the this country crossed the Rubicon to where we are now.
You have valid points. Others say it was the Civil War, with Lincoln suspending habeas corpus to try to quell secession. Whatever is the case, the seeds were sown long ago.