That was silly,the decline started in the 1840s with a new type of immigrant coming in.
You let that happen. So not smart now are your tough guy.
You shouda built a wall. LOL!
Democracy in America in 1835 defined America as Republican in government, democracy in the marketplace. We vote with our feet and money where to live, where to shop, where to worship.
The Civil War was one step in centralizing in DC the power of the states. But the Market Place was mostly left unchecked until Woodrow KK Wilson and William Jennings KKK Bryan. The rash of Constitution Amendments and Political processes greatly centralized Government power and control of the Marketplace.
Some would argue that centralized control is one of the factors that led to the depression. In 1933 FDR centralized banking and did a big move to centralize control of the Marketplace.
LBJ-Nixon did the biggest centralization of political and economic power. They centralized Welfare. They centralized immigration. Nixon made the states addicted to Federal money. Since Nixon state & local policy makers do not ask
What do the voters, taxpayers, citizens want?
What is best for the voters, taxpayers, citizens?
No State & local politicians now ask
How can I get more Federal money?
What is the best way to raise matching money to the Federal money?
Everything since LBJ & Nixon has been attempts to deal with the LBJ/Nixon USA cebtralizaton.
Above is a short 6 step history of the US.