When Walter Pincus, one of the most seasoned working journalists of the last 40 years, finally retired from his desk job as national security correspondent at the Washington Post the other day, he left a farewell message behind him. “Facts seem to be taking a back seat to arguments and slogans in what’s written and shown,” he wrote. “And that means the public is left to make up their minds on important subjects by choosing between arguments without knowing much about the facts that may or may not underlie them.”

Consider the threat from terrorism. “The Islamic State, as with al-Qaida, al-Shabab and other current terrorist groups, needs to be put in some perspective. After 9/11, a very wise intelligence officer told me in 2002, ‘We have turned 16 clever al-Qaida terrorists into a worldwide movement, seemingly more dangerous to Americans than the communist Soviet Union with thousands of nuclear missiles.’ Never at the height of the cold war did we institute the security actions at home that have been taken and are being contemplated to meet what’s been described as the current terrorist threat.”

A valedictory verdict to ponder after yet another week of video frenzy of Hunt the Jihadi across TV screens and print front pages as though the identity of a murderous Brit in a mask (plus five-year-old helper) was somehow a story to bite on, rather than what Pincus would call further drift “into a PR society where, sadly, public relations has become a key part of government and our politics”. For what else are the latest tabloid creations – “Jihadi John 2 and Junior” – doing but playing PR?

It’s a question that links, inextricably, to one aspect of journalism itself: the rise of the specialist correspondent.

Specialists come and go over the years, of course. Labour correspondents arose in a land of strikes and faded with that militancy. Religious correspondents are fewer and further between (like worshippers in the pews). But climate change has proved a rare recruiter of expertise – and terrorism, with Frank and Mark and Rohit and Simon dominating TV screens, is the growth industry du jour.

But the trouble with specialist beats is that you have to rely on the same old sources: you can’t cut yourself loose from special information streams. You’re in hock to the story providers. And the trouble with security correspondents is that your prime sources are there in the shadows, always willing and able to pull your strings.

MI6 has a designated press supremo to dole out tidbits to the media’s security correspondents. Photograph: Felix Clay/The Guardian

MI5 has a small team of serving officers who deal with the press, or, more specifically, a few “trusties”. MI6 has a designated press supremo recruited from Whitehall’s established machines. When the agencies have a message, then the means of delivering it is obvious. When there’s nothing much to say, that’s obvious, too.

“There are 800 British jihadists thought to be in Syria and Iraq,” ITV’s Rohit Kachroo concluded last week. “British spy services will be checking through their profiles to work out who it could be. But they haven’t concluded their investigation yet.” Over at the BBC, Gordon Corera sang exactly the same tune. The sources either give – or give nothing away. But they don’t welcome interlopers, mavericks, independents.

In any walk of journalism, expertise is always welcome. Kachroo won reporting awards early on; Corera writes intelligence history books on the side. They’re not to blame for what happens: it’s the nature of the game they have to play. Here’s John 2 and Junior starring in an Islamic State Productions video so gruesome viewers aren’t allowed to see it. Here’s a gush of front-page and bulletin excitement – and here’s the grave wisdom of the security press’s inner ring. Are there any firm facts on display? If so, would they matter? Is the fight against the Isis caliphate to be waged via TV fantasies or hard-won facts?

There is no escaping specialist journalism; sometimes more of it seems urgently needed. (I like the Ethical Journalism Network’s call for migration correspondents ie, reporters who know something about the history, the flows and the outcomes of refugee exoduses). But sometimes, too, the frailties have to be noted. Was Labour’s shambles of a reshuffle really the serial story of the week outside the reviled Westminster bubble? Can the Europe of referendum decision-making be squarely reported from a lobby correspondent’s desk? And, new lamps for old, are the authors of dodgy dossiers still in signing-off business?

Pincus quoted Barack Obama in that valedictory. Isis “is not an organisation that can destroy the United States… But they can hurt us, and they can hurt our people and our families. And so I understand why people are worried. The most damage they can do, though, is if they start changing how we live and what our values are.”

That’s reality. It is also where reality can go missing as our insecurity correspondents join the PR battle.