In a series of tweets posted in the early morning hours of 4 March 2017, President Donald Trump accused former president Barack Obama of having “wire tapped” phones at his Trump Tower headquarters in October 2016, just weeks before that year’s presidential election. President Trump likened this alleged activity to “McCarthyism” and “Nixon/Watergate”:

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

Is it legal for a sitting President to be “wire tapping” a race for president prior to an election? Turned down by court earlier. A NEW LOW! — Donald J. Trump (@realDonaldTrump) March 4, 2017

I’d bet a good lawyer could make a great case out of the fact that President Obama was tapping my phones in October, just prior to Election! — Donald J. Trump (@realDonaldTrump) March 4, 2017

How low has President Obama gone to tapp my phones during the very sacred election process. This is Nixon/Watergate. Bad (or sick) guy! — Donald J. Trump (@realDonaldTrump) March 4, 2017

Other than a vague reference to something that had been “turned down by court earlier,” the President’s tweets offered no documentation or evidence for the charges he was leveling at his predecessor in the White House. Speculation is that Trump was referring to claims made by syndicated radio host Mark Levin (echoed by Breitbart, and apparently based on a 7 November 2016 Heat Street article), that while Barack Obama was still in office, the FBI had sought a Foreign Intelligence Surveillance Court (FISA) warrant to investigate claims that a server registered to the Trump Organization was communicating with two servers registered to a Russian private commercial bank:

Two separate sources with links to the counter-intelligence community have confirmed to Heat Street that the FBI sought, and was granted, a FISA court warrant in October [2016], giving counter-intelligence permission to examine the activities of ‘U.S. persons’ in Donald Trump’s campaign with ties to Russia. Contrary to earlier reporting in the New York Times, which cited FBI sources as saying that the agency did not believe that the private server in Donald Trump’s Trump Tower which was connected to a Russian bank had any nefarious purpose, the FBI’s counter-intelligence arm, sources say, re-drew an earlier FISA court request around possible financial and banking offenses related to the server. The first request, which, sources say, named Trump, was denied back in June, but the second was drawn more narrowly and was granted in October after evidence was presented of a server, possibly related to the Trump campaign, and its alleged links to two banks; SVB Bank and Russia’s Alfa Bank. While the Times story speaks of metadata, sources suggest that a FISA warrant was granted to look at the full content of emails and other related documents that may concern US persons.

Breitbart summarized Levin’s claims as follows:

The Obama administration sought, and eventually obtained, authorization to eavesdrop on the Trump campaign; continued monitoring the Trump team even when no evidence of wrongdoing was found; then relaxed the NSA rules to allow evidence to be shared widely within the government, virtually ensuring that the information, including the conversations of private citizens, would be leaked to the media.

Obama spokesman Kevin Lewis denied the allegations, saying in a statement that “Neither President Obama nor any White House official ever ordered surveillance on any U.S. citizen” and that “a cardinal rule of the Obama administration was that no White House official ever interfered with any independent investigation led by the Department of Justice.”

Former Obama advisor Ben Rhodes also took to Twitter to say:

No President can order a wiretap. Those restrictions were put in place to protect citizens from people like you. https://t.co/lEVscjkzSw — Ben Rhodes (@brhodes) March 4, 2017

The Washington Post cited intelligence officials who opined they felt it unlikely that the Trump Tower offices had been wiretapped:

Some current and former intelligence officials cast doubt on Trump’s assertion. “It’s highly unlikely there was a wiretap,” said one former senior intelligence official familiar with surveillance law who spoke candidly on the condition of anonymity. The former official continued: “It seems unthinkable. If that were the case by some chance, that means that a federal judge would have found that there was either probable cause that he had committed a crime or was an agent of a foreign power.” A wiretap cannot be directed at a U.S. facility, the official said, without finding probable cause that the phone lines or Internet addresses were being used by agents of a foreign power — or by someone spying for or acting on behalf of a foreign government. “You can’t just go around and tap buildings,” the official said.

The Los Angeles Times also noted that:

It would be highly unusual for a sitting president to be aware of such [surveillance] requests. By blaming Obama directly, Trump accused the former president of reaching into a federal investigation and signing off on an illegal wiretap, which is a felony. If federal investigators did monitor Trump’s phones or computers lawfully, a court would have demanded information about potential criminal misconduct or unlawful foreign contacts. Such investigations are closely held and rarely, if ever, shared with the White House. It is possible Trump has no evidence his phones were tapped and is repeating unfounded reports circulating in conservative media circles.

In a separate Washington Post analysis piece about the controversy, Chris Cillizza wrote: