Well what the 'novel insight' from BTF is and the point being made, is the point about us being in an era of the drift rather than the era of the putsch - i.e. in contemporary times, and in contrast to the 20th century, we are not seeing so much a move away from the 'mainstream politcal centre' as you put it, but the gradual movement of the 'mainstream political centre' itself to the right
I should have quoted the wider quote from BTF from where that sentence was taken which makes it clearer as to what the difference between now and then is seen to be, which is somewhat more nuanced than the crude reductionist version that you paraphrased in your post above
It is undoubtedly the case that the rising vote for the European Far Right (in its electoral "respectable guize") during the long period of prosperity up to the 2008 Crash, based as it was mainly on anti immigrant sentiment, but also on the effects of globalisation on the skilled and unskilled working class, did indeed produce a nominal "drift" by the political centre to accomodate its rhetoric on immigration particularly - but in reality had very little impact on policy by the political parties of the political centre. Look at Italy , with the Northern League , with its deep historical roots to fascism - even to the Fascist "Salo Republic", actually In the coalition government for years - but what real impact did it have on Italian immigration policy ? Not much I'd say.
Since the 2008 Crash however, as the austerity has really started to bite, politics in France, Spain, Greece etc has certainly fragmented and moved away from the centre - but to the socialist Left as well as the Far Right and Fascist Far Right. In Greece , the country farthest along the road to economic and political meltdown however , far from your claim that :
"Gone is the need for a private army, as ‘strength on the street’ is no longer obligatory.
Unlike its 1930s forbears, what characterises fascism today is not the ‘putsch’ but what anti-fascists have referred to as ‘the drift’."
You are completely and utterly wrong....The harsh and quite obvious reality is that the state and capitalist class in this stage of social crisis still do indeed need the special physical and ideological forces of street fascism (heavily underpinned by state forces of course - just as in Italy in the early 20's and Germany in the late 20's and early 30's). Greece today far more resembles the Weimar Republic than a situation of "drift by the Centre" to the right. The Btf perspective was developed towards the end of the long neo Liberal boom, with bourgeois political centre politics in complete ascendancy pretty much everwhere, and the Socialist Left busted. . The "slow drift to the right by the Centre" , "with no role for street fascism" proposition may hold some water up to the capitalist crash of 2008, but today as the crisis deepens, of course the bourgeois parties of the centre will court the Far Right voters with anti immigrant and xenophobic policies, but as the crisis really impacts on countries like Italy, PortugaL, and France , it will once again be also an opportunity for the fascist Right and the socialist Left and revolutionery Left to grow at breakneck speed, as they have done in Greece. The State assisted fascist putsch - or military takeover with fascist "destabilisation assistance to justify it, has certainly not had its day quite yet.
One thing Is quite clear, as the crisis deepens in each country , the political centre fragments and lots of voters go to the Far Right, but lots also go to the Socialist Left and Far Left (underpinned by marxist philosophy and analysis) -- they certainly don't go to vote for some localist oriented non socialist organisation without a national , and internationalist, transformational perpective. The BtF analysis , with some real resonance in the peculiar "total hegemony of the neo Libera political centre" of the 1990's and up to 2008, has now been left far behind by the actual events on the ground.
