In the USSR's legal system, was everything illegal unless specifically allowed?

Question

Alan Dershowitz was recently interviewed by Michael Tracey on the latter's podcast. At 09:20 into the interview, Dershowitz makes the following claim regarding the USSR legal system:

... unlike in the Soviet Union, where everything you did was [a] crime unless there's a specific statute that says that what you did is legal; everything is illegal unless it's statutorily legal.

Now, I'm pretty sure that's false and merely anti-USSR cold-war-style propaganda, but I've never read up on the USSR's legal system - could I be wrong? Is there any basis for that claim?

Notes:

• This question does not regard the rest of that interview, which isn't about the USSR at all.
• I'm looking for official legal texts - constitution, "basic" laws, criminal/civil codes, etc.
• If you happen to think that statement is a joke, that doesn't matter; I just want concrete evidence (which, if this is a joke, would be evidence to the contrary of the claim).

Answer 1

According to the University of Cologne in Germany, the claim is not false for the time from the Russian Revolution until 1958. It is not entirely clear though if the claim is true for this time. It is fair to say, though, that the claim is false at least from 1958 onwards.

The principal is known as "nulla crimen sine lege" (no crime without law). So, as I understand it, if this principal is valid in a legal system, there has to be a law to make something illegal. In my interpretation that means everything is legal unless there is a law making it illegal.

In this explanation of the University of Cologne dealing with the principle it is stated that:

In Russia the principle was abolished during the Russian Revolution. According to the earliest Communist decrees, criminal courts were to render judgment on the basis of ‘revolutionary legal spirit’ (revolutionäres Rechtsbewusstsein). The Soviet Penal Codes of 1922 and 1926 permitted the criminalization of ‘socially dangerous acts’ through far-fetched reasoning by analogy. The nullum crimen principle was formally reintroduced in 1958 (Art. 6 Fundamental Principles of Criminal Legislation of the USSR and the Union Republics) but still remained inapplicable in practice for minor offences treated by non-professional Comrades' Courts. Today, the principle of legality is guaranteed in Art. 54 Constitution of the Russian Federation of 1993.

This means that the principle that establishes "everything is legal unless it is illegal (by law)" was not valid in the USSR from the Revolution until 1958. That said, this does not necessarily imply that everything was illegal unless it was legal (by law).

Answer 2

I don't have the source of a quote, but original sounds something like the following half-joke:

In America everything that is not prohibited, is allowed. In USSR everything that's not allowed, is prohibited.

This joke aims to highlight highly integrated political and regulatory system in the Soviet countries. This is also now called "vertical power structure" meaning that, in general, higher levels of hierarchy can dictate every minuscule detail of life on the bottom levels.

Currently, there is a petition #47914 on ROI website that collect official petitions from public for the Russian government, that says among other things (my lazy translation):

This petition asks goverment to explicitly add rule "all non-prohibited activities are allowed"

Idea that "everything not prohibited is allowed" stems from French revolution times (1789). [...] Unfortunately, currently Russia laws are not reflecting this, which leads to conversation such as:

— It is not prohibited, hence allowed

— Well, where did you read it? What law book?

Given that Russian laws are basically extension of the statutes of the USSR (some were copy-pasted from 1980s), I expect that USSR code didn't have explicit "what's not prohibited is allowed" spelled out.