"The American media, over the past year, has been trying to work out something of a mystery: Why is the Republican electorate supporting a far-right, orange-toned populist with no real political experience, who espouses extreme and often bizarre views? How has Donald Trump, seemingly out of nowhere, suddenly become so popular?"
Implied or stated assumptions in that part of the thesis don't wash.
Trump isn't far-right. A common critical theme levied against him by conservatives was his non-conservativism. He held (holds) centrist, progressive, or merely ideologically incoherent stances on several issues, as expressed at different times: abortion - all over the map; immigration - all over the map; trade - currently aligning with anti-trade Democrats; entitlements - generally against cuts (right-wingers are "supposed" to be for cuts); militarism and foreign adventurism - non-interventionist (aligns with different factions all over the political spectrum); gay (et al) rights - favourable (not far-anything).
Trump had no proper political experience, but he had a great deal of experience as a showman. Running for the presidency, showmanship is a workable substitute for political experience.
Trump did not come "seemingly out of nowhere". An article I can't find again (from a few months' back) identified how frequently Trump was welcomed as a media attraction and talk show guest over the years - until the point at which he declared for a Republican nomination and became persona non grata with many of the media personalities. One of the reasons he was popular (as a guest) was his penchant for saying things straight out, so it also isn't viable to argue that his views came out of nowhere, or that they suddenly crossed a line from acceptable (among those who helped him to air them) to unacceptable. Then during the election he nevertheless got a lot of support (airtime, exposure) from Democratic-leaning media who were happy to use him to mess up the Republican nomination.
I challenge the assertion that Trump is "so popular". If the article simply means strong popularity among his firmest supporters, that's a trivial truth that applies to almost every politician. If the article means popularity in any broader sense, Trump's low popularity is frequently commented on by media, which tends to deprecate the suggestion that he be regarded as popular.
Why is all of the foregoing relevant? Because it militates against the myth that Trump was too far outside some imagined parameters of acceptability and recognition. Consider this reformulation, which might have been written during the primaries: "The American media, over the past few months, has been trying to work out something of a mystery: Why is the Democratic electorate supporting a far-left, aged populist independent with recently tenuous ties to the Democratic party, who espouses extreme and often bizarre views? How has Bernie Sanders, seemingly out of nowhere, suddenly become so popular?"
If there were two populist candidates with substantial support (recollect the Democrats cheated their own nomination process to help guide Hillary to the win), characterized as representing the extreme right and extreme left, then a more sophisticated or broadly applicable hypothesis is required. How might Bernie Sanders vs Jeb Bush have resulted?
Now consider the proposition that there is still some mystery that Trump presents, and that it is explainable with reference to particular psychological profiling criteria. An election is a one-time event situated in particular and never-duplicated circumstances. Supposedly a particular set of answers to the questions predicted a vote for Trump. They also predicted a vote for the Republican candidate; a vote for the candidate who was not-Hillary; a vote for the candidate of the alternative party after a two-term presidency; a vote for the candidate perceived as more conservative (by convention, not by expressed beliefs); a vote for the candidate who produced a promised short list of potential USSC nominees; a vote for the candidate least likely to continue unrelenting lawfare against religious expression; a vote for the candidate not promising a continuation of "those jobs have gone away and are never coming back"; etc.
So a particular set of answers to the various psychological profiling questions predicts - what, exactly? Many factors were in play; many explanations are possible. How are all but one ruled out?
The article posits "Authoritarians are thought to express much deeper fears than the rest of the electorate, to seek the imposition of order where they perceive dangerous change, and to desire a strong leader who will defeat those fears with force."
All of that could be true: people fitting the profile have deeper fears, and long for the restoration of order when they perceive danger, and desire strong leadership in uncertain times. But other than the first speculation, it is basically a vanilla formulation of a commonplace observation: under pressure, people turn inward and seek relief. I suppose the people
experiencing increased crime in Baltimore would welcome more policing (authority).
"According to Stenner's theory, there is a certain subset of people who hold latent authoritarian tendencies."
Restate it without trying to pretend some people are inherently immune: under sufficient pressure, eventually nearly everyone exhibits latent "me-first" tendencies. A variation: when "the establishment" iterates through several election cycles without resolving problems, people turn to "not the establishment".
Trump was a "not the establishment" candidate, as was Bernie Sanders. (Was Sanders as certifiably eccentric as Trump, albeit in different ways?) All of the mystified academics and journalists and pundits and other people doing well in Bush-Obama America were not under pressure. Their "latent authoritarian" threshold had not been reached. For some on the left, their threshold had been reached, and they were turned toward Sanders. However, the current USSC nomination process has placed some of those comfortable people under a great deal of pressure, and it has manifested in interesting ways. Although they don't have an "authoritarian" leader behind whom they can coalesce (yet), they are certainly expressing much fear, perceived danger and risk, a remarkable narrowing of tolerance, and willingness to broach and discuss "extremist" solutions to their perceived plight.
"My interest is whether such methodology is useful when looking at our own political landscape."
Certainly. Crisis always creates opportunity. Make things difficult enough for Canadians, cycle through a few ineffectual or disinterested parliaments/legislatures, and watch the alternatives emerge.
I just disagree that it manifests in one particular way. And I'm tired of the decades-long pseudo-social-science effort to muddy the concept of (political) Authoritarianism and encourage people to equivocate with [psychological] authoritarianism, which when expressed at its worst in the past has sought to characterize "psychologically authoritarian" people as mentally ill.
It occurs to me that another way of framing "authoritarian" is "pro-social" (respectful, deferential, favouring the established order of society, etc).