I don't know the source you're quoting, but it's pure spin. The tax fraud and reporting violation were in direct service to the need to hide his foreign payments from Russian interests. You're also forgetting his guilty pleas for failing to register as a foreign agent (Russia again) and witness tampering (which is criminal obstruction of justice!).
This is all directly related to his work for Russia and Russian interests, in exactly the same way that Al Capone's famous tax evasion conviction was the result of his operation of a criminal organization.
Apologies, the source is wikipedia's page on Paul Manafort[1]. Also the article says he was involved with Yanukovich, not with Putin, but still in the worst case this is in the equivalent to the Biden-Poroshenko tape[2].
Tax fraud rendering you guilty of all the bad things you were ever accused of is not really sound logic. Also, I am not really defending Manaford - tbh after reading more on him, this whole Ukrainian foray seems to be one of his lesser offenses. But for example in the case of Flynn/Trump where prosecutors were taped discussing how they need to "find him guilty of anything or provoke him to cross the law", there is no doubt of bias.
> Tax fraud rendering you guilty of all the bad things you were ever accused of is not really sound logic.
The contention above was that there was "literally nothing to" Russian interference in the 2016 election. Manafort's convictions for activities related to his attempts to hide his Russian influence is clear evidence to the contrary.
I don't see anyone saying this makes Manafort guilty of "all the bad things he was ever accused of". But it makes him guilty of hiding Russian influence in the 2016 election, which was the point to be demonstrated.
This is all directly related to his work for Russia and Russian interests, in exactly the same way that Al Capone's famous tax evasion conviction was the result of his operation of a criminal organization.