In the most revealing glimpse yet into the rationale underpinning Special Counsel Robert Mueller's "pivot" toward investigating financial improprieties, obstruction and other potential crimes committed by Trump and his associates - instead of "Russian collusion" - a "secret" memo penned by Mueller's team was released by the DOJ last night.

In the memo, Mueller's investigators defend their decision to indict Trump campaign executive Paul Manafort on charges of financial crimes related to foreign lobbying. The heavily redacted memo cites heavily from Rosenstein's statement about the appointment of the special counsel. The special counsel quietly released it late Monday night and Bloomberg, the Wall Street Journal and others published details from the memo Tuesday morning.

And yet, in a bizarre sequence of events which has raised numerous eyebrows, the memo was dated August, 2017 - weeks after the FBI raided Paul Manafort's home in what was the first sign that he might soon be indicted, per Bloomberg, prompting speculation that the memo is merely an exercise in CYA.

In releasing the heavily redacted memo, Mueller argued that Rosenstein “left no doubt that the conduct that forms the basis for the indictment is within the special counsel’s jurisdiction.” Manafort faces a pair of indictments charging him with earning tens of millions of dollars in Ukraine, laundering much of that money, failing to register as a foreign agent and cheating on his taxes. Mueller also cited business ties between Manafort and the Russian oligarch Oleg Deripaska. Any investigation of links between Russia and the Trump campaign “would naturally cover ties that a former Trump campaign manager had to Russian-associated political operatives, Russian-backed politicians, and Russian oligarchs,” according to the 53-page filing in federal court in Washington. “It would also naturally look into any interactions they may have had before and during the campaign to plumb motives and opportunities to coordinate and to expose possible channels for surreptitious communications,” prosecutors wrote. “And prosecutors would naturally follow the money trail from Manafort’s Ukrainian consulting activities. Because investigation of those matters was authorized, so was prosecution.”

The memo was released to defend against claims made by Manafort's lawyers that Mueller extended beyond the scope of his investigation when he indicted Manafort and his former lieutenant Rick Gates (who has since plead guilty).

The classified August memo from Deputy Attorney General Rod Rosenstein was disclosed in a court filing by Mr. Mueller’s prosecutors. It seeks to counter arguments by Mr. Manafort’s lawyers that his indictment should be thrown out. Mr. Manafort has denied the allegations and pleaded not guilty to indictments filed by Mr. Mueller’s team in federal courts in Alexandria, Va., and Washington.

Manafort was famously charged with bank fraud, money laundering and failing to disclose his lobbying work on behalf of former Ukrainian President Viktor Yanukovich - a close ally of Russian President Vladimir Putin who abdicated in 2014.

Manafort was accused of laundering more than $30 million through offshore bank accounts and making false statements to obtain $25 million in bank loans.

In the letter, Mueller's staffers cited language within Rosenstein's initial memo appointing Mueller in May, claiming it offered Mueller a broad remit during his investigation.

“An investigation of possible ‘links and/or coordination’ between the Russian government in its political-interference campaign and ‘individuals associated with the campaign of President Donald Trump ’ would naturally cover ties that a former Trump campaign manager had to Russian associated political operatives, Russian-backed politicians, and Russian oligarchs,” the prosecutors wrote, citing language in Mr. Rosenstein’s original memo. In August, Mr. Rosenstein further clarified Mr. Mueller’s mandate in a classified memo that the special counsel attached in redacted form to its filings. In that memo, Mr. Rosenstein authorized Mr. Mueller to investigate whether Mr. Manafort committed potential crimes “by colluding with Russian government officials with respect to the Russian government’s efforts to interfere with the 2016 election for President of the United States, in violation of United States law.” It further stipulated that Mr. Mueller was permitted to probe Mr. Manafort for any crimes "arising out of payments he received from the Ukrainian government before and during the tenure of President Viktor Yanukovych."

Mueller has charged 19 people, including 13 Russians, since he was appointed by Rosenstein last spring. Of these, five have pleaded guilty, and Dutch lawyer Alex van der Zwaan, who pled guilty to lying to Mueller about his dealings with Gates, is expected to be sentenced in federal court in Washington on Tuesday, per the New York Post.

In summary, three questions have emerged: 1) Why released the memo now? 2) Why was the memo penned and signed after Manafort's home was raided; and 3)Will this memo's release make it harder for Trump to fire Rosenstein and/or Mueller, if he so chooses of course?