The bombing has made clear that the country is dotted with armed people who see nothing contradictory in defining themselves as patriots, while also preparing to wage war on their own government. In fact, there is nothing new about the deep distrust felt by some Americans towards Washington DC, especially in the western states, where unease over the exercise of federal power stretches back to the days the wagons rattled across the prairies towards the Pacific.
This hostility is rooted in contradiction and hypocrisy. On the one hand, there is a rugged individualism, born of the frontier spirit, and a deep frustration over the loss of control of vast stretches of forest and desert to a federal landlord. On the other, these states have been entirely dependent on federal support. Some of the areas in which anti-federalism is at its most virulent have for decades relied on large US military installations, as well as weapons and aerospace manufacturers.
This tension was never more in evidence than during the Carter presidency, when he proposed to base the MX (Missile Experimental) programme in the deserts of Nevada and Utah, a project which - had it been completed - would have been the greatest public programme in history, costing up to $100bn. The uproar was huge, and is still regarded as a defining moment in state-federal relations. In 1981, President Reagan scrapped it.
None of this, however, explains the paranoia of the so-called patriot's mindset, the conviction that America is about to fall into the hands of a Jewish-controlled so-called "New World Order" and can only be saved by a heavily armed modern-day version of the minutemen. Some of their deep conviction that the federal government is conspiring against them is rooted in real experience. Also, they have not forgotten the consequences of atomic weapons tests and covert radiation experiments on members of the public.
Mr McVeigh was one of the hundreds of thousands of young Americans who set off to the Gulf war with his ears ringing with the rhetoric from Washington about bloodying the nose of Saddam Hussein. After being pumped up for a fight, many young men in Operation Desert Storm were deeply embittered by President George Bush's decision not to enter Baghdad, and returned home full of resentment. After rumbing around the desert in his Bradley armoured vehicle, McVeigh is said to have come home a changed man, firing off letters to his local paper attacking the federal government.