So when did we lose Consrtitutional government and what was the cause?
Early 1900's. Liberalism.
So what did liberals do in the early 1900's that caused the loss of Constitutional government?
They ignored the U.S. Constitution. They assumed powers they did not have. They implemented policy that violated the Constitution. Here is a prime example:
Woodrow Wilson pushed for the Federal Reserve Act of 1913, which established twelve regional reserve banks controlled by the Federal Reserve Board, a new federal agency whose members were appointed by the President. This new federal system could adjust interest rates and the nation's money supply. Because it was authorized to issue currency based on government securities and "commercial paper" (the loans made to businesses by banks), the amount of money in circulation would expand or contract with the business cycle.
Here's the thing - if Woodrow Wilson wanted the power for the federal government to establish banks, adjust interest rates, and alter the nation's money supply, then what he should have pushed for is an amendment to the U.S. Constitution granting the federal government the power over those items. Instead, liberals just pushed ahead with their own bizarre agenda - law be damned.
How about another example?
Woodrow Wilson sponsored the Espionage and Sedition Acts, prohibiting interference with the draft and outlawing criticism of the government, the armed forces, or the war effort. Violators were imprisoned or fined.
Gee...that's not unconstitutional or anything. I mean, it's not like my 1st Amendment rights of Free Speech allows me to criticize the government, the armed forces, or a war effort. And the funny thing is - liberals sure as hell didn't abide by their own "Espionage and Sedition Act" when Bush was in office and we were embattled in conflict in Iraq.
Is that enough for you or do you require more?