Usually it's the United States that declares itself the exceptional nation, but this time Britain's the odd one out. While Europe, the US and much of the rest of the world have been shocked, shaken and otherwise gripped by the unfolding story of the NSA files, Britain has remained steadfastly unstirred.

Ever since the Guardian first revealed Edward Snowden's extraordinary evidence of NSA mass surveillance, the issue has been a central one in the American national conversation, furiously debated by journalists and politicians, on right and left alike. Rarely off the front pages, it prompted immediate action on Capitol Hill where no fewer than three separate bills are now passing through Congress aimed at turning back the tide identified by Snowden.

In Germany, the notion of vast, unseen eavesdropping became a cause celebre even before the revelation that the NSA was monitoring the phone of Angela Merkel. This, after all, is the land where the Stasi is a living memory, a place still haunted by that Lives of Others era when privacy was all but abolished. Across Latin America, Snowden was big news from the very beginning.

Yet throughout this period the British political establishment – whether in the press or in parliament – has remained stubbornly slow to move. Media outlets were late to cover the Snowden revelations in much detail, initially preferring to leave the story to the Guardian, even though Britain's own GCHQ operation is implicated as deeply as the NSA. It took the intervention of the head of MI5 to get the majority of the British press to start paying attention – not, mind, to the role of the British security services in this unprecedented exercise in global Big Brother-ism but rather to the actions of the Guardian, accused of "lethal irresponsibility" for revealing it.

It was the same story when the intelligence and security committee convened a parliamentary hearing at the start of this month – five months after the story broke. Unprecedentedly, it brought the heads of the three intelligence agencies – MI5, MI6 and GCHQ – into the daylight, answering questions together, in public and on camera for the very first time. But even then the standout moment was an implied attack on the Guardian, with the claim that the Snowden revelations had terrorists "rubbing their hands with glee", rather than an examination of how an agency of the British state came to be engaged in activities hidden from those charged with overseeing it.

What explains this contrast? An obvious answer is that Americans take privacy seriously. It's implicitly enshrined in the bill of rights, protected by the fourth amendment, which insists, "The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated …"

Indeed, within days of the Guardian's first revelations, the American Civil Liberties Union had filed a lawsuit arguing that the NSA's surveillance amounted to just such an "unreasonable" violation of Americans' private realm (to say nothing of their first amendment right to free, unhindered speech.) The protection of Britons' privacy is not nearly so direct or entrenched. We have to rely instead on article 8 of the European convention on human rights, which has been absorbed into British law for little more than a decade.

But the centuries-old protections guaranteed by the American constitution are merely part of a larger, defining difference between Britain and America. Put simply, Americans genuinely believe their government is meant to work for them, that it should be their servant, not their master. The US constitution begins with a declaration of where sovereign authority belongs: "We the people."

Much flows from that basic idea. If voters are the boss, with the president merely an employee on a four-year contract, then every agency of government is meant to behave the same way: like a subordinate, doing only what it is told.

This is why the NSA revelations are so shocking to Americans (as the Watergate revelations of 40 years ago were shocking). For they expose an arm of government acting without the permission, or even knowledge, of the American people and their representatives in Congress. For a nation founded in rebellion against overmighty power, constantly suspicious of the central state, the NSA's behaviour represents a violation of that basic American compact. Government and government agencies are meant to behave like the people's servants, not their masters.

Britons have no such starting assumptions. The people are not sovereign here, they never have been. We speak of parliamentary, not popular, sovereignty. We are used to power flowing from the top down, from the centre outward, and most of the time we accept it. We act as if it's natural for the state to be in charge and it's an act of generosity when it deigns to let in a little daylight. If an arm of the state insists on total secrecy, that seems reasonable to Brits in a way few Americans would ever accept. It's not a natural instinct for Britons to see, say, GCHQ as their employees.

And so outrage comes to us slowly. Without an individual victim, a human face, the NSA/GCHQ scandal has barely felt like a scandal at all. In the land of Magna Carta, it seems liberty can be eroded with scarcely a murmur.