Suffragette City David Bowie

suffragette detail.jpg
It is instructive to work with this song with the key window initially hidden, and then to work out where it must lie.
All of the chords are major. Consequently, chord shapes cannot be used to tell us what key we are in and where the allowed/forbidden territory lies, and where the possible centres lie. So does this mean the harmonic signposts are broken?
Surprisingly, no. The roots seem to be careful where they move. They move on the modal axis, and they take steps of different sizes. So perhaps tonal or modal territory simply lies hidden, and we can sense its location if we follow where the roots move.
The motion of the opening chords is very characteristic of an aeolian movement, with the opening chord as an aeolian centre (Aeolian I - VI VII I )
Just possibly the territory could be phrygian or locrian, but either would be very unusual with this kind of movement.
After a couple of repetitions, the movement continues modally upwards, confirming the initial centre as aeolian.
The movement hits a hypermetrical boundary (i.e the end of that line of the song) at aeolian IV - is there perhaps a hint of ambiguity as a dorian I? -
unlikely given the uncharacteristic direction of movement for Dorian.
Either way, we fall back to the original starting point to begin the next hypermetrical section.
And move straight back to an Aeolian IV (from which we recently came). Given the weak position in the hypermetre, this movement feels nothing like a harmonic dorian cadence. Il feels more like a simple contrasting location ( loosely an aeolian "subdominant" - or perhaps the further point reached linearly so far).
Down now to Aeolian VI, could this be a prelude for a rather boring repeat of the initial aeolian movement.
No ! Although the first and last chords are just what they would be in that case, the middle chord changes everything! The movement is reverse direction tonal! (i.e. plagal) More specifically, looking at the end point , this stunning move is a mixolydian cadence right up against the hypermetrical boundary!
Wonderful punning, yet highly contrasting, movement, but where does this leave us?
Well, continuing the direction of movement, after the hypermetrical boundary we are back at the "Other " location that led into this whole Mixolydian move, so we can do it all over gain.
Or, after hitting the mixolydian centre we can instead take a right turn creating a short Aeolian VII I cadence and we are right back repeatedly cadentially revving up to the start of the song again.