Manafort was attacked by much of the U.S. establishment media for selling his services in years past to the U.S.-ousted former president of Ukraine, Viktor Yauokovych, whom he helped elect. The fact that Yanukovych was the legal and democratically-elected president was irrelevant. The crime is he was "Russian-backed." (Not quite. The Russians had to pressure him to opt out of a trade pact with the EU that deliberately excluded Russia. And they didn't intervene to save him from having to flee for his life from the violent fascist rabble that the U.S. egged on to overthrow him, similarly to what they did in Iran in 1953.) 
Those of Manafort's ilk typically sell their services to various foreign governments, including despotic and tyrannical ones. No one raises an eyebrow over American shills promoting Saudi Arabia here, one of the most repressive and medieval regimes on earth. And Manafort couldn't gaze into the future to see that the U.S. would decide to overthrow his client and retroactively label that client an official Bad Guy. (We don't know if the U.S. was even then covertly moving against Yanukovych. Maybe someday WikiLeaks can tell us. The U.S. government certainly will never voluntarily tell. That's called "transparency" in the Orwellian language of U.S. political elites.)
But the successful assault on Manafort was more than just a case of singling out someone who is typically treated with discretion and respect by the establishment propaganda system. In fact it's the height of chutzpah. Because this was done on behalf of Hillary Clinton, and it just so happens that another member of Manafort's class of hustler, Lanny Davis, is a moral leper, propagandist for tyrants, P.R. man for the Honduran coup supported by Clinton and Obama, and a close associate of the Clintons, former special counsel to the last president Clinton. So where do the media allies of Clinton and those merely desperate to Stop Trump At All Costs get off with such a blatant double standard?
Davis charged a cool $100,000 a month to defend Ivory Coast dictator Laurent Gbagbo, who refused to leave office at the end of his term and murdered people to cling to power. (Unlike Yanukovych who offered to step down early to try and mollify the fascist mob that was setting cars, buildings, and policemen on fire in the streets. (Go watch the youtube videos- they literally lit policemen ablaze.) He also sold his services to the dictator of Equatorial Guinea. And there was his assiduous shilling for the Honduran coup. For pay, of course .
One useful conclusion we can draw about Trump from his willingness to throw Manafort overboard is this: contrary to the image he tries to project as a fearless tough guy who never backs down, we see that he is indeed susceptible to pressure, and willing to reverse course. More evidence of that are his verbal about-faces and two-steps when he gets a certain amount of heat for his statements. I predict that if he becomes president, the very powerful "national security" state- that is, the military-secret police combine- will be able to twist him like to pretzel to serve their goals.
After all, Trump has no real interest in foreign policy, no principles, and no goals except his own increased self-aggrandizement. So no impediments will be placed in the way of the Pentagon or the massive, multi-tentacled secret police apparatus (euphemistically called "the intelligence community").
But then, there are barely any limits placed on them now. And with all the rich blackmail material the secret police must have on Hillary, there won't be limits under a restoration of the Clinton reign either.
1] Not that Manafort has democratic scruples. He also worked for U.S.-backed Filipino dictator Ferdinand Marcos, and CIA-supported Angolan terrorist leader Jonas Savimbi. But maybe his worst crime was working for Reagan. For background on Manafort from an establishment media viewpoint, see. "Paul Manafort has guided dictators and strongmen, but can he manage Donald Trump?," Los Angeles Times, August 15, 2016. Notice how precipitately was Manafort's fall, coming soon after this piece.
For Manafort defrauding a Russian businessman out of $19 million, plus more on Trump and links to articles, see Swindler Trump's Presidential Campaign Run By a Swindler- U.S. Media Acts As Accomplices
July 27, 2016.
2] You can watch Davis speciously justifying his propaganda work for Honduran anti-democrats on Democracy Now! For the charge sheet against Davis see" Loathsome Lanny Davis Has More Blood On His Hands," December 28, 2010.