It wasn't so long ago that Asian people were the main target of white Australian racism. A political accident called Pauline Hanson stumbled into Parliament and whined that Asian people "don't assimilate".

The yellow press splashed this prejudice across the front pages, and John Howard endorsed Hanson's "freedom of speech" - the same Howard who campaigned for votes in 1988 with explicit anti-Asian racism.

Since then, the focus of the racist attack has switched. People of Islamic faith or Arab background are now the central target of Australian racism, and of the spooks and political police. At the time of writing, Melbourne man Jack Thomas has been banged up for five years for accepting a plane ticket home from al-Qaeda, and the yellow press still delightedly pins the label "Jihad Jack" upon him.

Racist politics constantly shift its targets. In the 1960s, Greek and Italian culture in Australia was derided. Too much garlic and so forth. Liberal politicians and newspaper editors campaigned against "Pommie shop stewards" in the 1970s.

The fact that Australian racism frequently shifts its goalposts is proof that it has no internal logic. It merely picks up the logic of establishment politics.

Anti-Irish prejudice began in Australia as a direct import from England. In the second half of the seventeenth century, English armies converted most of Ireland's best land to estates of the English landowning class. Native inhabitants of Ireland suddenly became "the Irish race", and deserving of English domination.

Australia's rulers developed from that landowning class. They always hated the prior occupants of the land, the Aborigines. But they also incited hatred towards the Irish.

The Irish often rebelled against English domination. There were many Irish rebels among the convicts who were transported to Australia. Colonial Australia was founded on ideas such as the only thing Irish understand is a good flogging.

All reminders of the Irish struggle were occasions for anti-Irish racism.

Many Irish convicts were peasants who spoke Gaelic, not English, and were Catholics. The first public Catholic Mass was not allowed until 1803. Then after the 1804 Castle Hill uprising, Mass was banned again for another 16 years.

The flogging parson Samuel Marsden proposed that the colony "continue the monopoly of Protestantism, particularly in the education of the children, and in a few years there would be no Catholics".

The Irish Famine of 1845-48 drove many Irish immigrants to Australia. Their arrival was greeted with hysteria about Australia being "swamped" by Catholicism, in terms very familiar to the modern hysteria about Australia "going Islamic".

In 1868 in Victoria, an Irishman, Henry James O'Farrell, attempted to assassinate a visiting royal, Prince Alfred. Explicitly anti-Irish and anti-Catholic organisations sprang up that held all Irish responsible for the sins of this "Fenian" - just as in modern Australia, all Muslims are held responsible for the "Jihadists".

The Sydney Morning Herald faithfully reported their meetings and racist propaganda. Colonial Secretary Henry Parkes repeatedly opined that Irish were just "jabbering baboons and disruptive troublemakers". NSW Parliament quickly passed the Treason Felony Act to crack down on disloyalty to the Empire.

In 1916 the rabidly pro-British Prime Minister Hughes attempted by referendum to introduce conscription for the war in Europe. Many Catholics and Irish, together with the political left, campaigned for a No vote. Pro-war campaigners, already experienced in pogroms against Germans and Turks in Australia, whipped up racism against the "disloyal" Irish Catholics.

Just as Islamic clerics are targeted for their supposedly "extremist" views today, Irish Catholic religious leaders were among the main victims. In 1920 the government tried to prevent Daniel Mannix, Archbishop of Melbourne, from re-entering the country unless he signed a pledge of loyalty to the British Empire.

Father Jerger, the parish priest in Marrickville, Sydney, was deported to war-ravaged Germany (he had lived there until he was two years old) after giving an anti-conscription speech from the pulpit.

Most of this was hysterically nationalistic, and only some of it was explicitly racist. But in Australia, nationalism shades seamlessly into racism.

Throughout the twentieth century, white Australian nationalism has promoted racism against many perceived races - sometimes the Irish, often Asians, always the Aborigines.

Up to modern times, the stated dislike of some Protestants for Catholics continues to be a form of anti-Irish racism, expressed in religious code.

Anti-Irish racism has ebbed, not because the Irish have "assimilated" into "Australian culture", whatever that is. However, Irish people have made major contributions to the Australian labour movement, and the struggle on the job for better living standards, which always promotes the realisation that there is only one race, the human race.

But the racist garbage still reappears, in new bins.

The fact that Australian racism shifts the target of its petty hatreds is also proof that it does not grow from human nature. It grows from politics. It can be fought, and defeated.