It's an open secret that Robert Mueller was a figurehead in the special counsel probe aimed at unseating President Trump, and that the actual operational boss of the team of Trump-haters was Andrew Weissmann.  Former U.S. attorney Joe DiGenova goes so far as to call the Mueller Report the "Weissmann Report."

With Mueller's testimony scheduled for Wednesday, leakers have revealed to John Solomon of The Hill that Weissmann pushed an effort to obtain incriminating testimony about Trump "collusion" from a Ukrainian oligarch, Dmitry Firtash, to the ethical limits and maybe beyond — offering to drop prosecution on a case pending in the United States in return for something to use against Trump.

The offer was declined, and the oligarch's attorneys state that this is because there was nothing to offer.  But what makes the situation scandalous is that an Austrian court — where the oligarch fled — has received documents on the offer that have led it to halt extradition to the United States to face trial on the case that Weissmann offered to drop, telling the world that something fishy indeed was going on.

Solomon writes:

The ink was still drying on special counsel Robert Mueller's appointment papers when his chief deputy, the famously aggressive and occasionally controversial prosecutor Andrew Weissmann, made a bold but secret overture in early June 2017.

Weissmann quietly reached out to the American lawyers for Ukrainian oligarch Dmitry Firtash with a tempting offer: Give us some dirt on Donald Trump in the Russia case, and Team Mueller might make his 2014 U.S. criminal charges go away.

The specifics of the never-before-reported offer were confirmed to me by multiple sources with direct knowledge, as well as in contemporaneous defense memos I read. (snip)

Weissmann's overture was wrapped with complexity and intrigue far beyond the normal federal case, my sources indicate. (snip)

 Mueller was appointed just two weeks earlier, did not even have a full staff selected, and was still getting up to speed on the details of the investigation. So why rush to make a deal when the prosecution team still was being selected, some wondered. (snip)

Prosecutors in plea deals typically ask a defendant for a written proffer of what they can provide in testimony and identify the general topics that might interest them. But Weissmann appeared to go much further in a July 7, 2017, meeting with Firtash's American lawyers and FBI agents, sharing certain private theories of the nascent special counsel's investigation into Trump, his former campaign chairman Paul Manafort and Russia, according to defense memos. (snip)

Weissmann's private observations and sharing of prosecutor's theories went beyond what prosecutors normally do in proffer negotiations and risked planting ideas that could lead the witness to craft his testimony, according to legal experts I consulted.

The Austrian court hearing Firtash's case against extradition apparently found the possible misconduct compelling:

After years of litigation, the U.S. Justice Department won a ruling in Austria to secure Firtash's extradition to Chicago. But then his legal team secretly filed new evidence that included the Weissmann overture, and Austrian officials suddenly reversed course last week and ordered a new, lengthy delay in extradition.

You really should read the whole thing.

Appearing on Hannity last night, Solomon discussed the revelations:

With Mueller cautioned by the Justice Department (letter here) to "remain within the boundaries" of his publicly released, redacted report.  Mueller will almost certainly refuse to answer questions about the Weissmann proffer — and any other embarrassing questions that GOP representatives might ask.

Graphic credit: YouTube screen grab.