Congratulations USA, on your 250th birthday except, the constitution of the republic was ratified 4th March 1789 making it the 237th birthday; it entrenched slavery and excluded native Americans, blacks couldn’t vote until 1870 and women until 1920, although this was before the UK permitted women to vote.
They adopted what they saw as the results of the English Civil War albeit with an explicit separation of powers, and guaranteed local democratic powers invested in the constituent states and the people by the 10th Amendment.
The growth of political parties, and the designed unaccountability of the Senate and Supreme Court can be seen today as critical weaknesses which one hopes are not copied by Europe’s constitutional reformers and that democrats in the US are able to fix.