I don't understand why people think this plea deal is "bad" for the Trump Administration.
According to the plea deal citing the "Conspiracy against the United States" charge here:
Superseding criminal information against Paul J. Manafort - The Washington Post
So on the face of this issue, it has NOTHING to do with Trump-Russian Election Conspiracy.
It
is all about Manafort's Ukrainian money laundering, tax fraud, failing to file foreign bank account reports, failing to register as a foreign agent for the prior issues, and lying to the DOJ about this activity. All but the lying occurred prior to 2016.
Recall, several Ukrainian and perhaps some Russian business parties were indicted over these "financial" crimes.
Therefore it is more likely than not whatever cooperation agreement Manafort made would be concerning witness testimony in
the prosecution of those indicted foreign co-conspirators in the money-laundering scheme.
I suppose it's possible Trump or some member of his family might have some connection to this pre-campaign period scheme, but I see no allegations as an "unindicted co-conspirator" nor any "singing and composing" of such as of yet.