WASHINGTON // Claims of a rising trend of Islamic radicalisation in the sprawling US prison system were largely debunked on Wednesday by expert witnesses speaking before US Congress. The response came in the second in a series of congressional hearings on radical Islam in America held by Peter King, a Republican congressman from New York and chairman of the Homeland Security Committee in the House of Representatives. Focused on radicalisation in American prisons, a phenomenon Mr King described as a "rising" threat", the hearings this week heard evidence from a bipartisan selection of legislators, prison officials and sociologists. But even as questions of American Muslim loyalties have made the leap into the mainstream political discourse in the US, the issue at hand - whether inmates were being recruited by Muslim clerics or other prisoners for future acts of terrorism - was largely batted down by expert witnesses as a fairly insignificant one. Bert Useem, a professor of sociology at Purdue University in Indiana, testified that only a few cases of terrorism had actually involved prison radicalisation. Citing evidence from academic studies, Mr Useem said that in only 12 instances since September 11 had there been "some evidence for radicalisation behind bars". Mr Useem concluded: "Muslim American terrorists are not especially likely to emerge from our prisons." Democrats used the hearings to argue for wholesale prison reform rather than a narrow focus on American Muslims. Laura King, a Democrat representative from Long Island, denounced the entire series of hearings as "racist and discriminatory". Blaming one group on the basis of religion or race, she said, is "flawed" and should not be done in the US Congress. Mr King remained unrepentant. Citing two cases in which American prisoners had converted to Islam and taken to terrorism, he said the issue was a real one and that to broaden the scope out from American Muslims to include other extremist groups in America such as white supremacist groups would mean "investigating nothing". Mr King's discourse on American Muslims has gained traction in the broader US political narrative. Herman Cain, a former pizza restaurant magnate and Republican presidential candidate, announced last week that he would require loyalty oaths from any Muslim members in his administration, should he be elected. "This nation is under attack constantly by people who want to kill all of us, so I'm going to take extra precaution," Mr Cain told CNN by way of justification. The former chief executive officer of the Godfather's Pizza chain of restaurants is currently polling second in Iowa, the first state set to vote in the Republican caucus. Yet the focus on a home-grown Islamic threat to US security appears to have little basis in fact. A February study by the Triangle Centre on Terrorism and Homeland Security, a joint department of Duke University and the University of North Carolina, found that the number of Muslim- Americans engaged in terrorist plots with domestic targets had declined from 18 in 2009 to 10 in 2010. The study revealed that tips from the Muslim-American community had provided information that led to a plot being thwarted in 48 of 120 cases involving Muslim-Americans. In all, the study found there had been 11 terrorist attacks on US soil, killing 33 people, perpetrated by Muslim-Americans since September 11, 2001. By way of contrast, the study pointed out there had been about 150,000 murders in America during the same period. Some argue that a far-more dangerous phenomenon is exactly the right wing extremism that Mr King is refusing to include in his hearings. The Southern Poverty Law Center (SPLC), a civil rights organisation based in Alabama, counted 1,002 active hate groups in the United States in 2010. The SPLC report mentioned white nationalists, anti-gay zealots, black separatists, racist skinheads and neo-Confederates, among others. The only Muslim element in that list is among black separatists, who in some cases adhere to the ideology of the Nation of Islam. American Muslim radicalisation is a "very small problem in the US", Mark Potok, the director of the SPLC's intelligence project, said yesterday. And it is an even smaller problem in American prisons "teeming" with white supremacist groups. "King comes to this with soiled hands," Mr Potok said. "There is no desire with these hearings to find objective truths. They are a joke, designed to demonise American Muslims." Moreover, he said, even though it is now 10 years since the September 11 attacks, "that's exactly what they are doing."