He looks at you rather as a history teacher would if you were a pupil who had never really bothered to learn the difference between Waterloo and Peterloo.
Sitting in his editor's study - a fusty, dark room in a Georgian house in Bloomsbury, London, which could never be called an office - he can't help giving a history lesson. Today it is on his favourite subject: the Conservative Party.
I ask meekly about his personal philosophy of Tory populism and he is delighted to explain the parallels between the dilemma of the Tories now and the party in the 19th century after the Corn Laws were repealed.
Frank Johnson has been at the helm of the ideological weekly of the right for just over three years. Despite gently rising circulation (now at 57,025) and the recent development that the magazine is actually making a profit, whispers against the incumbent editor and accusations that the magazine has lost its way are increasing in some quarters.
Sales soared under Mr Johnson's two eminent predecessors, Charles Moore and Dominic Lawson - now editors of The Daily and Sunday Telegraph respectively - and detractors say they are now peaking. There is no coherent Spectator ideology, say others.
"It needs originality of ideas and debate," says a respected contributor. "You feel it's caught between two stools. It's neither defining an ideological debate, but nor is it opening itself out to be a more general interest magazine."
There has even been talk of a strike at The Spectator among production staff disgruntled with Mr Johnson's habit of delaying until the very last minute what to put in the magazine. "He insists on all the different possibilities for a page being laid out and waits until they're right up against it and people are getting to the end of their tether." Think of industrial action by members of the Reform Club and you come close to imagining a strike at The Spectator.
When I repeat the editorial criticisms to Mr Johnson, he seems taken aback. "I think I have opened it up to quite a diverse body of views, particularly since the general election."
Though not given to showing off - he's reluctant even to list the things he likes about his magazine - he doesn't seem like a man who takes kindly to criticism - in fact, he seems to take it personally, a sign of someone who harbours a fundamental insecurity.
When I remind him that the liberal press had some fun at his expense after he predicted a Tory victory at the last election, he harrumphs, "Did they, hmm."
"He's chippy about being an autodidact surrounded by Oxbridge types," says someone who knows Mr Johnson well. "Even though he knows more than most of them, the chippiness is still obvious."
Mr Johnson, who was educated at Shoreditch Secondary School, where he dropped out before doing his A-levels, says he has now created the magazine he wants, with views from across the spectrum; to balance the rightwingers there are regular contributions by Sion Simon, a New Labourite, and a weekly column by Matthew Parris, a Tory of the liberal tendency.
From his own right-wing perspective, Mr Johnson may think The Spectator has broadened its appeal, but the apolitical reader flicking through may think otherwise: right-wing heavies such as Bruce Anderson, Paul Johnson, Stephen Glover and Taki appear in every issue.
Whatever their politics, the terrible trio of Johnson, Glover and Taki have given The Spectator its best sport this season. The spat began when The Spectator writers challenged the veracity of The Guardian's investigation into the activities of the two former Tory ministers, Neil Hamilton and Jonathan Aitken. "I believe Neil Hamilton never took those brown envelopes stuffed with cash, though I don't have any evidence," says Mr Johnson.
The Guardian recently devoted two pages to cataloguing the magazine's obsession with it - perhaps indicating that The Guardian may be equally obsessed with The Spectator.
Alan Rusbridger, The Guardian's editor, has sent Mr Johnson two letters asking what sort of publication he thinks he's editing. "I've never heard of a national newspaper editor doing something like that," he ponders. "I think Alan Rusbridger just isn't used to anyone disagreeing with him." Perhaps, though, Mr Rusbridger just resents The Spectator's columnists casting aspersions on his journalists without any evidence. "They're free to write what they want. I think it's all very amusing," Mr Johnson says.
Like any good Tory boss, Mr Johnson dismisses the talk of a strike among his staff: "It just isn't going to happen," he says. "I am very late in deciding what to put in on Tuesday night, because I have to make sure that it's still relevant when people buy it two and a half days later."
And of the ever-present rumours that the magazine's owner, Conrad Black, is about to sack him and appoint someone else as editor, he says quite simply: "I'm sure if Conrad Black wasn't happy with the magazine he would tell me."
The magazine's publisher, Kimberley Fortier, says Mr Johnson is a "very commercially aware editor, much more tuned in than lots of editors of glossies". This week the venerable magazine sees a redesign, bringing more colour and a clearer layout aimed, Mr Johnson says, at "addressing that perennial question, bringing younger readers in without losing the older ones".
Has Mr Johnson no fear that The Spectator is in danger of becoming an anachronism? "I think it is essential reading because we're better informed about New Labour than any other publication," he responds.
Mr Johnson is so enthusiastically dedicated to his baby that you can't help but hope he is right. But within the broader context of a rapidly modernising media and society, you have to wonder.