If true, this is a blockbuster, which vindicates one of President Trump's most famous and most roundly criticized tweets, and which may have far-reaching implications.  CNN is claiming in an exclusive report based on unnamed sources (which always means caution is necessary) that:

US investigators wiretapped former Trump campaign chairman Paul Manafort under secret court orders before and after the election, sources tell CNN, an extraordinary step involving a high-ranking campaign official now at the center of the Russia meddling probe.

The government snooping continued into early this year, including a period when Manafort was known to talk to President Donald Trump.

This seems to vindicate President Trump's roundly ridiculed assertion of wiretapping in the Trump Tower.

Terrible! Just found out that Obama had my "wires tapped" in Trump Tower just before the victory. Nothing found. This is McCarthyism!

— Donald J. Trump (@realDonaldTrump) March 4, 2017

Manafort not only spoke to Trump in this period, but lived in the Trump Tower.  Also vindicated are Devin Nunes, who was forced to recuse himself from the Russia probe for revealing this to the president and public,  and Mark Levin, who was roundly criticized for being the source for Trump's tweet about wiretapping in Trump Tower.

The information was fed to Robert Mueller's team that has been searching for a crime.  It was the Comey-led FBI in the Lynch-led DoJ, in the Obama presidency, that reportedly used the FISA Court to obtain a warrant, quite possibly based on the phony dossier, that has provided material to get Manafort and pressure him to find something to squeal about and catch a higher-up.  The legitimacy of that warrant now is in question.  I am not a legal scholar, but it seems to my eyes that a fishing expedition powered by a phony warrant lacks legitimacy.

There could be legal trouble ahead for Comey and Clapper.  As Kristina Wong noted at Breitbart:

The Justice Department and the FBI denied that Trump was being wiretapped.

Comey later in March disputed Trump's claims – in testimony that lawmakers could now find misleading.

He told the House intelligence committee, "With respect to the president's tweets about alleged wiretapping directed at him by the prior administration, I have no information that supports those tweets, and we have looked carefully inside the FBI."

The New York Times also reported that Comey had said Trump's claim was false, and that he had asked the Justice Department to publicly reject it, according to the BBC.

James Clapper, the former Director of National Intelligence, also told Congress that intelligence agencies did not wiretap Trump, nor did the FBI obtain a court order to monitor Trump's phones, according to the BBC report.

The New York Times has just revealed some more details of the level of bullying being employed as Team Mueller puts the squeeze on Manafort to squeal and find some sort of Trump crime to trade for leniency in whatever charges they may be able to find against him.

Paul J. Manafort was in bed early one morning in July when federal agents bearing a search warrant picked the lock on his front door and raided his Virginia home. They took binders stuffed with documents and copied his computer files, looking for evidence that Mr. Manafort, President Trump's former campaign chairman, set up secret offshore bank accounts. They even photographed the expensive suits in his closet.

The special counsel, Robert S. Mueller III, then followed the house search with a warning: His prosecutors told Mr. Manafort they planned to indict him, said two people close to the investigation.

The moves against Mr. Manafort are just a glimpse of the aggressive tactics used by Mr. Mueller and his team of prosecutors in the four months since taking over the Justice Department's investigation into Russia's attempts to disrupt last year's election, according to lawyers, witnesses and American officials who have described the approach. Dispensing with the plodding pace typical of many white-collar investigations, Mr. Mueller's team has used what some describe as shock-and-awe tactics to intimidate witnesses and potential targets of the inquiry.

Mr. Mueller has obtained a flurry of subpoenas to compel witnesses to testify before a grand jury, lawyers and witnesses say, sometimes before his prosecutors have taken the customary first step of interviewing them. One witness was called before the grand jury less than a month after his name surfaced in news accounts. The special counsel even took the unusual step of obtaining a subpoena for one of Mr. Manafort's former lawyers, claiming an exception to the rule that shields attorney-client discussions from scrutiny.

The Times delicately presents this hardball as "set[ting] a tone."

Professor Jacobson wryly observes:

A 17th attorney was added, inching Team Mueller closer to the size of the entire U.S. Attorney's Office for the State of Rhode Island and Providence Plantations.