And in recent times, critics have been given plenty of fodder. During the 2010-11 Scottish soccer season, hate crime associated with these two clubs stretched to the unthinkable after some bitterly contested matches: Both hoax and live letter-bombs were sent to several high-profile individuals connected with each.
Now, with the 2011-12 soccer campaign under way – and the first Celtic-Rangers match set for Sunday – a raft of new police measures and tougher legislation are being drafted in a bid to root out the problem. And all eyes will turn to Glasgow to see whether the new focus has any effect on the words emanating from the stands.
A new bill going through the Scottish Parliament involves the creation of new offenses, including the incitement of religious hatred at or around a soccer stadium. This would involve a significant raising of maximum sentencing powers available to courts. Offensive songs often heard at grounds, too, are to be banned.
Though Rangers and Celtic have voiced concerns over the tougher legislation – Celtic stated innocent fans could be criminalized – a survey found 90 percent of Scots agree with the new measures.
Yet, some fans on both sides of the Rangers-Celtic divide contend their songs are not sectarian but political. They point to lyrics' references to the Irish Republican Army, Northern Ireland's pro-British paramilitaries, and other groups involved in the violence that gripped Northern Ireland for decades. But just as the line between politics and sectarianism was blurred in "The Troubles" of Northern Ireland, so too is it difficult to find in Scotland.
The modern roots of this dispute in once Catholic Scotland, which broke with Rome in the 1500s after the Protestant Reformation, can be traced to the influx of Irish Catholics to Scotland during the 19th and 20th centuries, and institutionalized discrimination against Catholics. Later, bigotry found a theater in soccer.