It was a sign of the arrival of a new age of paranoia in the murky basement of American political life. Last week an astonishing operation by the FBI and police broke up a rightwing anti-government Christian militia group, seemingly intent on sparking a revolution.

If that sounds far-fetched, don't be fooled. The anger that defines the feelings of a large swath of the American electorate in an age of bank bailouts, economic crises and Republican scare-mongering over "creeping socialism" has found fertile soil.

The extreme dangers were amply illustrated by exposure of the Hutaree militia, based in the small towns and deep woods of rural Michigan. According to the indictment against them, they had been plotting for two years to kill police officers. Their plans apparently involved an assassination, followed by a bomb attack on the funeral procession. Their sick hopes were to spark a nationwide anti-government uprising.

It was a stark warning that the threat of terrorism from America's rightwing subcultures is as dangerous as that from Islamic extremists.

Washington Post writer Eugene Robinson wondered if Americans were now living through a mirror-image of the 1960s. Then it was the extreme left that boiled with rage and plotted to overthrow the government via groups such as the Weathermen. "The danger of political violence in this country comes overwhelmingly from one direction – the right, not the left," Robinson wrote.

Not that the leading conservative lights of the Republican party and the Tea Party movement would agree – or take any responsibility. They continue to warn of the creeping role of government in the economy, dub Barack Obama a socialist (or a fascist) and speculate about the possibility of him being born abroad or a closet Muslim.

The Constitution itself, they warn, is under threat. Nowhere are such thoughts more dangerously spread than by rightwing media pundits such as Glenn Beck and Rush Limbaugh. Indeed, Beck plans to write a novel espousing many of his political beliefs. His setting, according to the Philadelphia Daily News, is an America in turmoil where a citizens' group, called the Founders Keepers, ends up fighting a civil war.

Beck, and his equally alarmist fellow travellers, should be careful what they wish for. As the Hutaree were keen to show, some people are willing to take them at their word.