Carl Bernstein received an email from Bob Woodward the other day. “Can you believe this?” it read, “44 years!”

It was a reference to President Richard Nixon’s resignation on 8 August 1974, following years of dogged reporting by the Washington Post’s Woodward and Bernstein into the Watergate break-in and cover-up.

The most famous double act in journalism were in their early 30s at the time and, like the Beatles when they broke up, could have been forgiven for assuming that the biggest story of their career was behind them. But then along came Donald Trump with Watergate echoes too loud to ignore. “Woodstein”, as the affectionate compound noun has them, are elder statesmen now but the hunger is still there.

Woodward’s upcoming book, Fear: Trump in the White House, shot to number one on Amazon.com within a day of its announcement. It is expected to be the most authoritative account yet of the first 18 months of the administration.

Bernstein was among three CNN reporters who recently broke the story of former Trump lawyer Michael Cohen’s allegation that the Republican candidate knew in advance of the June 2016 meeting between his son, Don Jr, and Russian representatives.

Bernstein is clearly galvanised by covering a big story again but there is no hint of glee. “I would hardly call covering Trump a joyous experience,” he told the Guardian. “I think that this is a dangerous time for America, that we have a president with no regard for the rule of law or for the truth. I say those things not pejoratively. It’s reportorially established and I think that’s what’s so extraordinary.”

Some parallels with Watergate are inescapable, he said. “Obviously there are similarities, not least of which is part of the story is about undermining the electoral process. You’re also dealing with cover-ups in both instances and special prosecutors.”

But the differences from that era appear more profound to him. Bernstein explained: “This is worse than Watergate in the sense that the system worked in Watergate and it’s not apparent yet that the system is working in the current situation. No president has done anything like Trump to characterise the American press and its exercise of the first amendment as the enemy of the people, a phrase associated with the greatest despots of the 20th century.”

Reporters Bob Woodward, right, and Carl Bernstein, whose reporting of the Watergate case won them a Pulitzer prize, in the Washington Post newsroom in 1973. Photograph: AP

Currently writing a memoir of growing up in the newspaper business from age 16 to 21, Bernstein has seen many presidents come and go but Trump is “sui generis”, he believes. “One might have thought that Richard Nixon was but they’re very different. Even using the word demagogue and saying that the president of the United States is a habitual liar, one would not have said that about Nixon. He lied often to hide his criminality but what sounds pejorative when I’m on the air is reportorially about him being a habitual liar, about what demagoguery is.”

Woodward, 75, and Bernstein, 74, never stopped reporting or writing. Bernstein is a political commentator for CNN whose books include A Woman in Charge: The Life of Hillary Rodham Clinton. Woodward has worked at the Post for nearly half a century and is now associate editor. He has written several bestselling chronicles of presidencies from Nixon to Barack Obama.

Fear: Trump in the White House, out next month, is his 19th book and one of most eagerly awaited. Publisher Simon & Schuster teases that it will show the “harrowing life” of the Trump administration, drawing upon “hundreds of hours of interviews with firsthand sources, contemporaneous meeting notes, files, documents and personal diaries”.

The title is based on a remark that Trump made to Woodward and another Post reporter in a 2016 interview: “Real power is through respect. Real power is, I don’t even want to use the word, fear.”

Former defence secretary Leon Panetta, who in May chaired a panel discussion with Woodward, Bernstein and Trump’s first chief of staff, Reince Priebus, said: “I think a lot of the old juices are flowing. The experience both of them had with Watergate in many ways has prepared them to deal with the challenges of the Trump administration. They’re now in the same position as they were before as young reporters.”

Yet the political and media environment has changed in unthinkable ways. The Post office where, under swashbuckling editor Ben Bradlee, Woodward and Bernstein hammered out reports on typewriters, and where newspapers ran off underground presses, has been demolished. Now owned by Amazon billionaire Jeff Bezos, the Post has moved into hi-tech headquarters geared up for the digital age. From Facebook to Fox News, the media is fragmented and polarised with disputes over what constitutes truth itself.

Panetta said of Woodward and Bernstein: “Their basic expertise was in trying to find the truth but we’re in a time when facts are under attack. They’re dealing with a more challenging world where the mere fact of who they are doesn’t carry the kind of respect it once did.”

In 1974 they co-wrote the book All the President’s Men, which was turned into a Hollywood film starring Robert Redford and Dustin Hoffman and featuring gloomy car park meetings with the mysterious source “Deep Throat”. It might now be tempting for Trump-weary liberals to fantasise about Woodward and Bernstein reuniting to save the republic again.

Asked if there is any prospect of another collaboration, Bernstein replied: “I wouldn’t rule anything out altogether. There’s certainly no plans but we run things by each other and we counsel each other.”

The men’s professional and personal relationship was said to have become strained for a time in the 1970s but they are otherwise very close. “We talk a couple times a week and have for years and obviously there’s some things we can’t share with each other but we have a pretty good idea. We keep a dialogue going about Trump and the story and the presidency. We’ve been doing this for 45, 46 years.”

And does it trouble Bernstein that, as automatically as Laurel and Hardy or Lennon and McCartney, the duo is commonly referred to as Woodward and Bernstein rather Bernstein and Woodward? “Not in the least,” he said cheerfully. “I don’t think you worry about that sort of thing.”