Imagine looking at a 3D image with those special red and blue glasses but closing one of your eyes.

Some parts of the image would disappear if you closed your left eye and other parts would be missing if you closed your right eye.

Politics often leads a person to close a metaphorical eye. People only see what they want to see and shut out anything uncomfortable which contradicts their world view. Evidence is no longer evidence at all but rather white noise to be filtered out, or ammunition to be twisted and used against the other side.

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The existence of a large amount of this type of confirmation bias in politics is a conclusion one is bound to draw after reading a new report by the One Law for All campaign: Siding with the Oppressor: The Pro-Islamist Left.

In the past decade or so some progressives have found themselves - either through political expediency or something worse - on the side of the far-right.

Some have intentionally thrown in their lot with what any politically astute person would recognise as fascism, while others have simply been unwilling to acknowledge that fanatical movements don’t always comprise of white skinheads with bad tattoos and football shirts.

The result, as the report notes, has been an anti-war movement working enthusiastically with those advocating the murder of homosexuals, a left-wing Mayor of London embracing a man who said Adolf Hitler had been sent by Allah to punish the Jews, and a group set up ostensibly to oppose fascism warmly welcoming religious fascists into its own ranks.

Because the left doesn’t police its borders in the way that the right has learned to do - social democrats like to pretend the far-left are on the same side as them - extremists regularly sneak into the mainstream on the back of ostensibly progressive front groups.

A good example is Unite Against Fascism.

Launched in 2003 as a response to the electoral activity of the British National Party, UAF spends most of its time these days organising counter demonstrations against the EDL.

An honourable way to pass the time, you might think.

UAF’s definition of what constitutes fascism, however, is a peculiar one. Not only are those advocating the resurrection of a fascistic Islamic caliphate seemingly not worth opposing, they have been actively welcomed into the UAF fold by the leadership.

One of UAF’s vice-chairs is Azad Ali, affairs co-ordinator for the Islamic Forum of Europe, an offshoot of the far-right Islamist group Jamaat-e-Islami. As well as quoting an Islamist militant on his website in 2008 who claimed it was a religious obligation to kill British and American soldiers, Ali is on record as saying of democracy that “if it means, you know, at the expense of not implementing the Sharia, no-one’s gonna [sic] agree with that. Of course no-one agrees with that”.

On telephoning UAF’s office to clarify the group’s position on Islamic fascism, One Law for All was told by a UAF representative that there was “no such thing”.

The lack of concern about Islamism extends to the so-called anti-war movement.

Anas al-Tikriti, a current Vice-President of the Stop the War Coalition, has said that calls for an Islamic state should “not scare us…or bring about a negative reaction”.

Speaking of the Jews, Tikriti has also criticised the Muslim Council of Britain for dropping its plan to boycott Holocaust Memorial Day, which he said was a principled stand.

As you make your way through the report you notice that the people who have brought Islamists inside the progressive tent crop up in various left-wing campaigns again and again - usually to accuse those expressing concern about extreme religious conservatism of Islamophobia.

As Maryam Namazie of One Law for All puts it: “the likes of the Stop the War Coalition, the Socialist Workers’ Party, Unite Against Fascism, Islamophobia Watch, and the Respect Party…are there as prefects to silence dissenters and defend islamism as a defence of ‘Muslims’.”

Nor have the individuals mentioned in the report ever been disowned by the political left. On the contrary, they remain ubiquitous and their organisations are still treated as if they were respectable progressive outfits.

Over the past decade or so not only have the actions of the ‘pro-Islamist left’ given an indication of what some of the supposedly idealistic really think of the people they should be defending - the LGBT community, women, Muslims and ex-Muslims but an unwillingness to speak out against Islamism has allowed racist groups like the English Defence League to pose as vocal defenders of secularism.

In a disastrous irony, the pro-Islamist left has ended up in the same place as the white far-right. The perception of Muslims as synonymous with Islamism - criticism of Islamism is characterised as criticism of Muslims - is precisely the view taken by groups such as the EDL.

The mystery is why the left has welcomed into its ranks individuals who by any definition sit on the ultra-right.

The answer, I suspect, lies in the fact that many Islamists exhibit a pathological anti-Americanism that is quite attractive to a certain type of degenerated progressive.

As for all the other bad things the pro-Islamist left are seemingly to ignore in embracing Islamism - did I mention confirmation bias?