This year's 9/11 anniversary brought rancour among non-Muslim Americans and fear to Muslim ones, writes Graham Usher in New York 11 September used to be the day Americans came together, bound by the memory of the slaughter of 2,700 of their people when Al-Qaeda hijackers ploughed aircraft into the World Trade Center (WTC) in New York and Pentagon in Washington. Today the anniversary tears Americans apart, ostensibly over a plan to build an Islamic community centre and mosque two blocks from the WTC site, but actually over perceptions of Islam and the place of Muslims in America. Last Saturday -- nine years later -- the two Americas joined figurative battle over the site of the proposed centre. Those supporting the so-called Cordoba House project marched. They were multi-ethnic, multi-faith and multi-coloured, driven by the drumming of Buddhist monks, and swelled by numerous left-wing, anti-racist and pro-Palestinian groups. Their basic message was that Islam was not responsible for 9/11 and that Muslims, like other faiths, had a constitutional right to build their "prayer houses" wherever they wanted. Those opposed were squeezed into two pens behind the site, once a coat factory. They were overwhelmingly white, and exclusively Christian. Many were Tea-Party activists from the far right of the Republican Party, backed by ex-marines, Hells Angels and a handful of Arab Christians. Their message was that to build a "victory mosque" next to the WTC site was to insult thousands of Americans who had "perished at the hands of Muslims" on 9/11. Each demonstration drew about 2,000 people. Add another 2,000 who had joined a vigil in favour of the centre the night before, and you'd think Americans supported tolerance and religious freedom by about two-to-one. You'd be wrong. However extreme some of the Tea-partiers' rhetoric ("Mosques are for burning" was one slogan -- by no means the worst), their opposition to the location of the centre chimes with mainstream American opinion. Polls show nearly 70 per cent against the building of a "mosque" near the WTC site out of "sensitivity" to the victims' families: a sensitivity that only makes sense if you think Islam bears some blame for the atrocity of 9/11. Many Americans do. The same polls show that most view Islam unfavourably, with a sizeable minority believing that it "encourages" violence against non-Muslims. Americans say they feel more afraid of "radical Islam" today than they did three years ago, let alone nine. Such attitudes have permitted a peculiarly American kind of anti-Muslim xenophobia. The run-up to this year's 9/11 anniversary was marked not only by the furore over Cordoba House. It also saw attacks on mosques across the country. In New York, a Bangladeshi taxi driver was stabbed in the neck after being asked his thoughts about the Islamic centre by a white passenger newly returned from Afghanistan. (The driver had said he was against it). Finally, there was the attempt by Pastor Terry Jones to make 9/11 "international burn a Quran day" because "Islam is of the devil". He was eventually dissuaded by United States President Barack Obama, General David Petraeus and just about every other Western and Muslim leader. But by then the threat alone had fired protests in Afghanistan and deadly violence in Indian-occupied Kashmir. Hostility to Islam in America is as old as the founding fathers but such overt expressions are rare. Muslims here say they feel more isolated than at any time since 9/11. The Islamic Society of North America talks of "a growing tide of fear and intolerance". What opened the gates? One reason, ironically, is the fact of having a president who one in five Americans think is Muslim, and many are convinced is an immigrant. With Barack Obama in the White House whatever inhibitions the Republican Party once had about exploiting 9/11 for partisan ends have been cast to the wind. Republican candidates for Congressional elections in November have been unabashed in milking the Cordoba House controversy to bring out the anti-Muslim vote, with one going so far as to "equate" the constitutional right to build a mosque with the right to burn the Quran. "How can you equate the burning of any person's scripture with the attempt to build interfaith dialogue?" answered the centre's Imam Feisal Abdel-Raouf. But there is another, deeper reason. Since 9/11 the US military has waged un-winnable wars against "extremist" Islam in Afghanistan, Iraq, Pakistan, Yemen and Somalia, to name only the obvious countries. These have cost the United States thousands in lives and trillions in treasure, and generated a hatred of America across large parts of the Muslim world. But they have also brought the war home, and changed America as a society. A recent investigation by The Washington Post showed that the US government now has 263 organisations engaged in the "war on terror". This is aside from a new Department of Homeland Security, which, with 230,000 employees, is the largest state bureaucracy after the Pentagon and the Department of Veteran Affairs. This national security state has various tasks but a primary one is to monitor, check and occasionally annul the rights of America's seven million Muslims and any others that work, study or pass through here. All, given America's wars abroad, are potential "national security threats" at home. But such a state has also added legitimacy to a popular and populist culture that equates Islam with violence and Muslims with "terrorism". At the height of the Cordoba House crisis, President Obama said America "is not and never will be at war with Islam". But that's not what it feels like to American Muslims. They "feel under siege", says Akbar Ahmed, author of Journey into America: The Challenge of Islam. Nor is it how their lives are portrayed by a media that turns cranks like Terry Jones into global actors, paints Imam Raouf as an apologist for Hamas, and presents a centre for interfaith reconciliation as a symbol of Islamist supremacy. That's why so many American Muslims are scared. "We really feel we are sitting on a tinder box," Ahmed told the BBC last month. "One catalyst and things could really get out of hand. The New York mosque could just be that".