I think you are confusing politics with stability. In the case of impeachment, the system worked perfectly. A partisan house along with others outside of the house went for impeachment and it stopped in its tracks by the Senate. If the government was unstable, other crap would be happening including assassinations etc.
No the system did not work perfectly. The infiltration did not meet enough resistance to be prevented. Black mail has captured several members in gov. The system is filled with traitors. Unless that is addressed it will collapse.