WASHINGTON (AFP) - There has been fierce debate in the United States about President Obamas reaction to the Iran protests with some saying he has not given enough support to the Tehran demonstrators. By minimizing policy differences between incumbent Mahmoud Ahmadinejad who claimed victory in the disputed presidential election and challenger Mir Hossein Mousavi, whose supporters have flooded the streets, Obama has angered conservatives and put the White House and some Democrats on the back foot. Senator John McCain, Obamas Republican rival in last years US election, described the presidents response as tepid, and blasted him for abandoning the fundamental principles of the US. Obama has stressed that universal rights of peaceful protest should be honoured in Iran, but has refused to pick sides in the showdown. He warned that US meddling in Irans internal politics would be counterproductive, and vowed to push forward his engagement policy with Iran. It is a stance that has left some lawmakers fuming. Their silence on the issue of human rights violations is very troubling to me, said Eric Cantor, the number two Republican in the House of Representatives. America has a moral responsibility to stand up for human rights around the world and to condemn the abuses that are occurring in Tehran today, he said. Influential Democratic Senator John Kerry offered a retort, writing a commentary in the New York Times under the title With Iran, Think Before You Speak. We are all inspired by Irans peaceful demonstrations, the likes of which have not been seen there in three decades, Kerry wrote, adding that watching heartbreaking video images of Basij paramilitaries terrorising protesters, we feel the temptation to respond emotionally. The last thing we should do is give Mr Ahmadinejad an opportunity to evoke the 1953 American-sponsored coup, which ousted Prime Minister Mohammed Mossadegh and returned Shah Mohammed Reza Pahlavi to power. Experts and the US media have also seized on the debate. The Washington Post noted in an editorial that the White House was carefully calibrating positive messages about the protests in an effort to avoid giving the government in Tehran an excuse to portray the demonstrators as pro-American. The New York Times more bluntly suggested that Obama worries about coming out on the wrong side of history. Steve Clemons, an expert at the New America Foundation, a Washington research centre, said Obama made a mistake to dismiss the differences between Ahmadinejad and Mousavi. Obama may not have meant to but he conveyed disrespect for the process at play now in Iran and what is important for Obama and others in the national security establishment to understand is that Irans election is not over, Clemons wrote. Robin Wright, of the Woodrow Wilson Centre, told AFP that Obama is wisely showing restraint for now. Maybe down the road he needs to say something, but the minute we weigh in, the minute we say the things that we obviously feel, is the moment that America becomes the defining force, that the (Iranian) regime blames us for everything, said Wright, a former Washington Post political correspondent. Daniel Brumberg of the US Institute of Peace said he views the issue as a debate about the legacy of the Bush administration. In 2002 president George W. Bush lumped Iran, Iraq and North Korea into an axis of evil, part of a neoconservative policy to promote pro-American democracy by pressuring such governments until they crumble. With Obama its a debate about how much the US should be at the forefront, trying to speak about pushing for democracy, said Brumberg, a Middle East expert. The debate has agitated the Obama administration. The New York Times reported that Secretary of State Hillary Clinton had hoped Obama would lend more vocal support to the demonstrators. And Vice President Joe Biden privately believes Obamas remarks on Mousavi were a mistake, say sources familiar with Bidens position on the matter. A State Department spokesman, Philip Crowley, insisted Obama and Clinton agreed on Iran. I dont think theres any daylight between the position of the president and the position of the secretary of state, Crowley said.