From the angry and menacing to the more relaxed and thoughtful, there have been a variety of reactions to the Guardian's revelations about the extent and depth of the National Security Agency's data surveillance programme. A surprising range of voices from both right and left have voiced shock at the revelations – not least Republican congressman Jim Sensenbrenner, who wrote for the Guardian: "I authored the Patriot Act, and this is an abuse of that law."

Collectively, the reactions have lacked coherence. At one and the same time Barack Obama and James Clapper, his director of national intelligence, condemned the "hype" in the media while arguing that the debate the leaks had inspired was "healthy for democracy" and "a sign of maturity". Which is it? Are the leaks "rushed and reckless", providing enemies with a playbook to avoid detection? Or is it now good to have a public debate leading to a more appropriate balance between the conflicting interests of security and civil liberties than exists now, especially in the US?

Congress has (some say) had "full oversight" over the secret programmes while others – including in those charged with oversight – insist that Congress has been kept profoundly in the dark about US government interpretations of the Patriot Act, introduced in the wake of 9/11. It will be a bad day when people don't trust Congress and the judiciary to make the judgment that they themselves are not allowed to make, Mr Obama suggested. But, except for the privileged few, most congressmen did not know and were aghast to learn that records were being kept of every call made in the US, or that the NSA had potential access to billions of emails, messages, internet chats and social network pages.

Congress and the media were so clueless about the extent of the intrusion that they failed to heed the hint Senator Mark Udall, a member of the intelligence committee, dropped in 2011 when he warned that the "intelligence community can target individuals who have no connection to terrorist organisations".

Mr Obama and William Hague yesterday used the same argument: trust us to keep your secrets. The legal framework in both countries is stronger than it once was, and ministerial oversight is, in principle, strong too. It is impossible to know how many times ministerial or judicial oversight has been exercised to curb the intrusions of the security services, if they ever have, because that information, too, is secret. The argument about public trust therefore stands on shifting sands. How can a government appeal to the public's trust in legislative and judicial oversight, if that trust has been abused by the extent to which privacy has been invaded – especially when public trust in the government is so fragile?

There is, however, little inconsistency to be shown in Mr Obama's attitude to whistleblowers. They are to be hunted down and prosecuted with the full force of the law. When we say Mr Obama, there have been several incarnations of the man. In 2008, the presidential candidate said the following about whistleblowing: "Acts of courage and patriotism, which can sometimes save lives and often save taxpayer dollars, should be encouraged rather than stifled, as they have been during the Bush administration." As president, his administration has attacked more national security whistleblowers as criminals under the Espionage Act than all previous governments combined.

The actions of whistleblowers may embarrass governments. But where legislatures and judges fail, whistleblowers keep open the only channel left for public accountability. They do so for no personal gain, and at considerable cost to their own freedom. They are public servants, because only the public stands to gain from their acts of conscience. What is needed in Britain are clear statements, under parliamentary questioning today, about GCHQ's access to the material gained from the NSA's global intrusions. We have not yet had them.