Today, there is no perfect regime in this world. Some of the answers here give people the impression that the interviewer asked "What do you think is your greatest weakness" in the interview, and the candidate replied "I take things too seriously". If you know American politics, you will find many problems. Otherwise, there will not be a large number of political economists studying solutions.
The separation of powers in the United States makes the judiciary (court), legislation (parliament) and administration (administrative agency) independent of each other.
There is no completely clear dividing line between the three powers.
The judiciary can use its power to interpret the Constitution to change the actual judicial rules, thus realizing the function of the so-called "second legislature" or the so-called "shadow legislation". Therefore, the judicial rules in the United States can be changed by an unelected institution.
Sometimes, this is a good thing. For example, the Supreme Court ruled that apartheid was illegal and accelerated social development.
But this is not always a good thing. For example, it was decided not to allow blacks and whites to get married, and there was no upper limit on corporate political donations.
In a recent ruling that same-sex marriage is legal, a dissenting judge said, "Who do you think you are?" What he means is that these justices have no right to "interpret" the Constitution at will according to their own values and make major changes to the legal system.
Legislative power belongs to parliament. However, this kind of "second legislation" actually damages the efficiency of the general work of the parliament. Some ethnic minorities who are unsuccessful in the parliament can go to court at any time to sue the relevant bills for unconstitutionality. However, unconstitutional litigation is protracted and costly. Not only that, the court is also an "administrative veto institution". Any administrative resolution made by the administrative authorities may be sued to the court for being unconstitutional. The social cost is extremely high. (European governments have a higher threshold for unconstitutional review. )
The original pattern of separation of powers was that the legislature demarcated the behavioral boundary for the people and the administrative organs, and the judicial organs were responsible for managing this boundary. However, due to the importance of common law cases, the ambiguity of American constitution and the precedent set by the earlier Supreme Court. Judicial intervention in administration and legislation has been abused.
It is necessary to know whether same-sex marriage is legal or not, and it should be changed by the legislature. Here, however, the Supreme Court has gone beyond the bubble and imposed the will of several unelected justices on the whole country. Even if the legalization of gay marriage is a progressive move, this method should be vigilant. After all, the Supreme Court's decision is not only glamorous in history.
Similarly, the legislature can also intervene in the executive branch. Within the legislative branch, there are also some ways to check and balance the majority, such as obstructing the proceedings.