Anti-Soviet Agitation and Propaganda (ASA) (Russian: Антисоветская агитация и пропаганда (АСА)) was a criminal offence in the Soviet Union. To begin with the term was interchangeably used with counter-revolutionary agitation. The latter term was in use immediately after the first Russian Revolution in February 1917. The new Criminal Codes of the 1920s introduced the offence of Anti-Soviet Agitation and Propaganda as one of the many forms of counter-revolutionary activity grouped together under Article 58.
article 58.10 of the RSFSR Criminal Code was in force throughout the period of Stalinism and Article 58:10, "propaganda and agitation that called to overturn or undermining of the Soviet regime" was punishable with at least 6 months of imprisonment, up to and including the death sentence in periods of war or unrest.
The offence was significantly revised in the post-Stalin Criminal Code of the RSFSR, introduced in 1958. Article 58.10 was replaced Article 70, Anti-Soviet Agitation and Propaganda and its definition brought it closer to Western legal norms, although it had few if any parallels in the criminal codes of democratic countries.
It was defined as: 
- propaganda or agitation with the purpose of undermining or weakening of the Soviet power or with the purpose of committing or incitement to commit particularly grave crimes against the Soviet state (as defined in the law);
- the spreading with the same purposes of slanderous fabrications that target the Soviet political and social system;
- production, dissemination or storage, for the same purposes, of literature with anti-Soviet content
Article 70 was considered by critics of the Soviet System to be a grave violation of freedom of speech. It was one of the two the main legal instruments for the prosecution of Soviet dissidents, the other being Article 190 of the RSFSR Criminal Code. Other means of control were extrajudicial, such as the use of punitive psychiatry or the generalised offence of the social parasitism. In particular, the clause about literature targeted the samizdat. Article 70 was finally abolished in the perestroika years and the new Russian Criminal Code, effective from 1 January 1997, contained no parallel.
While the clauses was phrased using the provision "with the purpose of", official commentaries (referred to as "Additions and Explanations to..."), as well as the actual legal practice made it sufficient to assert that the prosecuted person of sane mind must have realized the malicious implications of their utterances.
This article was the most common tool in fighting Soviet dissidents. Shortly after the Sinyavsky-Daniel trial, the Soviet Penal Code was augmented with a weaker Article 190-1, Dissemination of knowingly false fabrications that defame the Soviet state and social system (1967). It basically repeated the Article 70, with the omitted provision of the "anti-Soviet purpose". The penalty was lower: up to 3 years of imprisonment.
Petro Grigorenko in his memoirs wrote that any critique of the Soviet government or events in the Soviet Union was easily classified as ASA. Dissemination of any information which was not officially recognized was classified as "Anti-Soviet slander". In this way nearly all members of Helsinki Watch were imprisoned.