While it is welcome and overdue that the Supreme Court on Monday finally adopted a code of ethics for its judges, the approach is seriously flawed as it lacks an enforcement mechanism. Instead, it remains up to each judge to decide whether to dismiss the case in a particular case.

Until Monday, every state and federal judge was bound by a code of ethics, with the exception of the most important lawyers: the justices of the U.S. Supreme Court. Recent revelations of serious ethical lapses by several justices, most notably Clarence Thomas and Samuel Alito, have highlighted this absence.

The court has the lowest public approval rating in history, and while there are certainly many reasons for that, the lack of a code of ethics has certainly contributed to its loss of legitimacy. This was a self-inflicted wound. There was no reason why the judges could not adopt the same code of ethics that all other judges are required to follow.

And on Monday, the Supreme Court finally set the same bar for its members. With little fanfare, it published a code of conduct for justices of the United States Supreme Court, signed by all nine justices. This was accompanied by a brief statement from the court explaining that the absence of a code in recent years has led to the misunderstanding that the judges of this Court, unlike all other lawyers in this country, regard themselves as not limited by some ethical rules. The court said that we are promulgating this Code to remove this misunderstanding.

The code itself is unobtrusive. It is based on the American Bar Associations Model Code of Judicial Conduct, which is used nationwide. In terms of structure and content it is largely the same. The only thing that is remarkable is how long the court delayed taking this easy and obvious step and how much pressure it took for the court to agree to it.

But there’s a crucial problem with what was released Monday. It remains up to each judge whether he or she should be excluded from hearing a particular case. There is no evidence of any change in this disturbing practice.

In fact, a court commentary accompanying the new code highlights the harm when a judge withdraws because no other judge can replace the absent member. But this wrongly assumes that having nine judges is more important than avoiding a bench tainted with ethical improprieties.

There are already many cases in which the court functions without all nine judges, for example when one is ill or when there is a vacancy that has not been filled. After Justice Antonin Scalia died in February 2016, there were only eight justices for the next fifteen months due to the Senate’s refusal to consider President Obama’s nomination of Merrick Garland. Having eight judges is not ideal, due to the danger of ties and leaving issues unresolved. But avoiding ethical clouds is more important.

No one should be a judge of himself or himself. There must be a mechanism for determining when a justice should be revoked that does not leave this entirely up to the individual. The documented ethical lapses in recent years certainly provide a basis for questioning whether judges are sufficiently sensitive to these issues.

There are many different approaches to this that could work. My colleague Jeremy Fogel, a former federal judge, proposed to the Senate Judiciary Committee in May that the chief justice appoint three retired federal appeals court judges to decide recusal issues. There are many excellent retired judges who could be appointed to this position. An alternative would be to have recusal issues for one judge to be decided by the other eight judges. The danger with this approach is that the judges could develop a norm of respecting each other and refusing to meaningfully enforce the code of conduct.

However the code of ethics is structured, there must be an enforcement mechanism for the code of ethics to have meaning. Trust us is never an adequate answer, especially when it comes to ethical issues. The legitimacy of the courts, and the foundation of the rule of law, require the court to take the next step and provide a way to enforce the rules it has adopted.

Erwin Chemerinsky is a writer for Opinion and dean of the UC Berkeley School of Law. His latest book is

Worse than nothing

: The dangerous fallacy of originalism.