AMNA NAWAZ: The nine justices of the Supreme Court handed down a surprise unanimous decision today, binding themselves to a new code of ethics.

Here's how they explained it, writing: "The absence of a code has led in recent years to the misunderstanding that the justices of this court, unlike other jurists in this country, regard themselves as unrestricted by any ethics rules.

To dispel this misunderstanding, we are issuing this code."

To unpack the court's new rules, we welcome Kathleen Clark, a law professor with Washington University in St. Louis specializing in legal and government ethics.

Professor Clark, put this moment in context for us.

For the first time in the court's 234-year history, it's adopting a code of ethics.

How big a deal is this?

KATHLEEN CLARK, Washington University of Saint Louis: This is not a very big deal.

It does show that the Supreme Court can read the room.

It knew that it had to do something to address the political and ethics crisis that it finds itself in.

But in terms of substance, this new code does very little.

And it provides no new mechanisms for holding justices accountable when they violate the rules.

AMNA NAWAZ: Well, let's tick through some of that public pressure from the reporting that has been laid out.

And I do want to take a moment to, in particular, note the many reports by ProPublica breaking news on this front over the last seven months.

You're seeing a few of those stories right there.

They raised concerns over donor influence, failure to disclose gifts, failure to recuse from certain cases.

So, Professor Clark, does any of this -- is any of this addressed by the new code?

KATHLEEN CLARK: This new code addresses none of that.

It doesn't address donor influence.

It doesn't address what will happen when justices fail to disclose gifts.

It does address the recusal problem by saying, nothing will change.

It views recusal as a decision for an individual justice.

And if a justice fails to recuse, the court won't do anything about it.

AMNA NAWAZ: So, you have read through the whole code now.

What does it do?

And if it doesn't do anything, why do you think all nine justices signed onto it?

KATHLEEN CLARK: I believe that the justices, all presidentially nominated and confirmed by the Senate, are, in that sense, politicians.

And they realize that the court is in some jeopardy, in some political jeopardy, because of the scandals uncovered by ProPublica and other journalists.

So they felt pressure to take some sort of action, perhaps to stave off Congress from taking action and imposing an actual ethics code that would provide accountability.

So, I think that this should be seen really as a political document, as a way of addressing a political problem that the court had.

AMNA NAWAZ: You mentioned that congressional pressure.

One of those who has been calling for Congress to impose and enforce a code of ethics is Democratic Senator Sheldon Whitehouse.

He tweeted some of his concerns, which get to a point you raised earlier about enforceability.

He said: "The question is enforcement.

Where do you file a complaint?

Who reviews it?

How does fact-finding occur?

Who compares what happened to what's allowed?

That is where the rubber hits the road."

So, Professor Clark, do I hear you saying none of that is addressed in this code and there is potentially still a role for Congress here?

KATHLEEN CLARK: Oh, there's definitely a role for Congress here.

And, yes, this code is utterly silent.

It's basically a failure to address those really important questions of who is it that will hold justices accountable, and how will they be held accountable?

And if I could just add one thing, ironically, the court touts the fact that it imposes mandatory ethics training on the court's employees.

It does not impose mandatory ethics training on the justices.

And that's where the failure has been.

AMNA NAWAZ: Well, here's the question, because we have heard some of the justices publicly say they support a code of ethics.

We have recently heard just earlier this fall from Justices Coney Barrett and Elena Kagan.

Here's what they had to say then.

AMY CONEY BARRETT, U.S. Supreme Court Associate Justice: I think it would be a good idea for us to do it, particularly so that we can communicate to the public exactly what it is that we're doing in a clearer way than perhaps we have been able to do so far.

ELENA KAGAN, U.S. Supreme Court Associate Justice: It would help in our own compliance with the rules.

And it would, I think, go far in persuading other people that we were adhering to the highest standards of conduct.

AMNA NAWAZ: Professor Clark, do you think there was a divide or there is a divide among the justices on how this should be addressed?

KATHLEEN CLARK: I don't -- I'm not privy to the justices' conversations among themselves, but you could hear in both of those quotations a concern with public perception.

And that, I think, is the bottom line about this new code.

It's a way of addressing public perception, rather than addressing the heart of the problem, which is a lack of accountability.

AMNA NAWAZ: So, when it comes to public perception, we know the court has suffered a decline in public trust, like a lot of American institutions, in recent years.

Does this code help at all with that trust and building it back up?

KATHLEEN CLARK: I don't believe so.

I believe what would actually help matters for the Supreme Court is for it to adopt an accountability mechanism, something like what has been suggested by, I think, Professor Stephen Vladeck and others, an inspector general, some kind of mechanism for investigating allegations of wrongdoing or violations, and as a way of actually holding justices accountable when they fail to get the law.

AMNA NAWAZ: That is Kathleen Clark, law professor at Washington University in St. Louis, joining us tonight.

Professor Clark, thank you.

We appreciate your time.

KATHLEEN CLARK: Thank you very much.