Our own "founding fathers" knew that no system could stop someone determined enough to destroy it from inside.

"The dignity and stability of government in all its branches, the morals of the people, and every blessing of society depend so much upon an upright and skillful administration of justice, that the judicial power ought to be distinct from both the legislative and executive, and independent upon both, that so it may be a check upon both, as both..."

— John Adams

And our government doesn't have that necessary firebreak. Justice is part of the Executive.

Source: https://www.mass.gov/guides/john-adams-architect-of-american...