Why does the Schengen rule apply to american tourists returning from Germany to the usa
yes
Yes it does. Otherwise, why would there be laws?
In the us, for the president, its 4 years
The President is not in civil service. He is an elected official. GS grades do not apply.
I am not an expert but I am guessing the 6 month rule or the where you lived the longest rule would apply.
George Washington
Congress must set its own pay.
First, US Presidents do not "rule", they "serve" the citizens of the US. (Monarchs "rule", but democracies never "rule".) Second, F.D.R. served in the office of the President from March 4, 1933 to April 12, 1945.
The US did not exist in 1714. The country was under British colonial rule.
No one is above the Rule of Law, not even the US President.
It does not apply.