Not so long ago, a decision by the US and other western countries to close their embassies because of a risk of terrorist attacks, citing "chatter" from intercepted communications between al-Qaida-inspired jihadists, would have been treated overwhelmingly with unquestioning respect.

That the response may be very different now is recognised by members of the US senate intelligence committee. The closure of 25 US embassies across North Africa and the Middle East demonstrated just how important the National Security Agency (NSA) and its ability to bug huge amounts of communications, was in protecting the security of Americans, they insisted.

That they needed to go so far out of their way to defend the NSA is testament to growing concern among many other members of Congress and the US public, according to opinion polls, since the disclosure by Edward Snowden, to the Guardian and Washington Post, of the extent to which the NSA is intercepting the personal communications of Americans and non-Americans alike.

We might be forgiven for the thought that the embassy closures provoked by terrorist threats were all very convenient – even though they came after attacks on prisons in Iraq and Libya and elsewhere, reportedly leading to the escape of many al-Qaida-inspired extremists.

The US state department in Washington said the decision on Monday to extend the embassy closures was taken "out of an abundance of caution". That might be understandable given the political fallout of the attack on the US consulate in Benghazi last September and the death of the US ambassador Chris Stephens – fallout now fuelled by reports that up to 35 CIA operatives were in the Libyan city at the time trying to procure weapons for rebels in Syria.

Scepticism is healthy. For far too long the intelligence agencies of the US – and Britain – have been allowed to hide behind a wall of secrecy as they hoisted the flag of "national security" before which everyone else must genuflect. Secret courts and congressional committees in the US, and parliamentarians in the UK, tasked with monitoring the activities of the agencies, have been seduced too easily by the privilege of being allowed to be party to those secrets.

That scepticism may lead to potentially dangerous cynicism is the fault of the failure adequately and convincingly to hold the intelligence agencies to account. The detail of operations, certainly recent ones and ones planned for the near future, may need to be protected by secrecy. But as other commentators have pointed out, the US government, in its approach to secrecy and in particular in its attitude towards WikiLeaks and Bradley Manning, has not been able to distinguish between a US Apache helicopter crew shooting unarmed men, including Reuters journalists in Iraq, and the exposure of operations that might conceivably threaten the lives of innocent Americans.

The US and UK securocracies have not been able to distinguish between the invasion of privacy and a legitimate need to protect the public from terrorist threats. Until they do so, they will sacrifice the "benefit of the doubt" approach, the public's trust, that they will need to depend on in future.