Replace with what? Please Sir tell us your ideal constitution
Checks and balances doesn't work.
Legislative branch must be abolished.
President must be able to override SCOTUS.
Think of the US Govt like a corporation:
President = CEO
Cabinet = C-Suite (Press Secretary = Chief Marketing Officer)
SCOTUS = Customer Support
Alphabet Agencies (FBI, CIA, NSA, DOJ, DOD, etc. = Divisions.
The entire goal of congress is to cockblock the president and this is so bad that they've had to go around the US Cons, by giving the president executive orders, basically the ability to legislate laws. In practice all congress does is in fight and block reform. This is EXACTLY what occurred in the Roman Republic too. They generate 0 value and instead cause gridlock and division. They must be abolished.
SCOTUS should be customer service. They interpret the rules and enact them. But because of the "separate of powers" BS our SCOTUS passes laws. They take the responsibility to pass controversial laws because the legislative branch doesn't want to take heat during re-elections. Since SCOTUS can block the president, we have Kritarchy. Imagine if Apple or Google or Microsoft customer support could override the CEO. Insane.
I know the founding father's vision was to prevent tyranny but in practice they created a system that guarantees incompetence -> low trust in the system -> people wanting to overthrow the system, This is why many other nation that tries to implement our system eventually reject it and go back to a dictatorship because at least that system works, able to pass laws. This is not the best form of govt, it's the absolute worst.