Celtic fans identify with hero Neil Lennon
Even now, when the supporters are increasingly polarised and the antagonism that shapes the Old Firm rivalry has become capable of reaching darker and more violently threatening extremes, there is a sense of Rangers and Celtic being tightly bound together.
The reality of their existence is to provide the means of expression for some old, resentful hostilities, and when the two sides meet again tomorrow, for the seventh and final time this season, the wonder is how the two sides will endure all the tension, the anger, the bitter indignation, and even the angst, of the occasion.
For the away support at Ibrox, much of it will be released in the 18th minute, when they plan to stand and applaud their manager, Neil Lennon.
He once wore the No18 on his back, as a combative midfielder who played with a fierce, almost self-righteous sense of his own authority; now, he represents to the club's fans so many aspects of their identity: Irish background, Catholicism, an unabashed defiance, and persecution.
This first full season in management has seen Lennon occasionally lost to his own ill-discipline, become embroiled in a confrontation between his club and referees and the Scottish Football Association, and be the target for death threats that escalated from bullets in an envelope to a viable parcel bomb.
To Celtic fans, these parcel bombs are treated as proof of a sectarian attitude they believe to still be prevalent in Scotland, and to be perpetuated by Rangers fans.
To the followers of the Ibrox side, this is considered an inaccurate slur (since the criminal act of an individual or group cannot be held to be representative of their support as a whole).
But then Rangers supporters are currently under investigation by Uefa for allegedly signing sectarian songs in Europa League games last month, and it is undeniable that two offensive anti-Catholic chants, The Billy Boys and No Pope Of Rome, have been heard again this season, having previously been subdued by self-restraint.
Lennon, in his stark bullishness, has been a central figure, and on the touchline at Ibrox he will be the focus of much of the edginess; this galvanises him, since he is never more alive than when faced with the demand to be emphatic and commanding, but in quieter, more reflective moments, when he thinks of his partner and child also being affected by the strain, then a truer perspective is revealed.
“Anyone in any walk of life shouldn't have to deal with something like this,” he says.
“It is uncomfortable, you see your face every hour on the news and after a while you start thinking 'is that me they are talking about?' I've had this for 10 years, but I don't want to say you get used to it, because you never do.
“But it is not going to deter me from doing what I want to do. This is the greatest privilege in my life, to manage this football club, and the support I've had from the fans and my close family and friends has been my strength.”