Checks and Balances
The government can check each other to see if there are any overpowering them. The judicial can check the power of the legislative branch by declaring a law unconstitutional. The legislative branch can check the power of the executive branch by declaring one of his actions unconstitutional and check the power of the Judaical by taking the judges out of the office. Executive branch can appoint judges as well. So each branch are very equal and they can not overpower each other.