In the UK in 1993 it was discovered that information on overspending and waste in a single government programme, amounting to £130 million, was kept from members of parliament for three years and was initially reported in secret. The independent prosecutor's report on the Iran-contra arms scandal revealed that the then president had permitted false accounts of it to be disseminated to members of Congress and encouraged schemes to circumvent its ban on such sales. In 1994 in the UK much media attention was given to the declaration by a government minister that it was sometimes right to lie to parliament. The statement was confused by a further qualification that although required to answer questions accurately a minister was free to choose not to reveal all information pertinent to the question.
All government ministers spend a fair proportion of their time misleading parliament. Learning how to do so and how to deploy the many civil servants whose promotion depends on exhibiting the relevant skills of verbal dissimulation, is an elementary task for every politician with ambition. Crafting an appropriate response to a question that reveals as little as possible is the essence of ministerial politics.
Ministers alone are accountable to parliament in a manner which generally excludes ministerial responsibility for situations in which a civil servant had misled the minister (including failure to make available intelligence assessments). For every error made by ministers, parliament can obtain any relevant information it needs, overriding any limitations on its capacity to overcome any systematic suppression of information by government. Under certain circumstances it is legitimate for ministers to respond to questions from parliament by half-truths to discourage further inquiry, notably in the interests of national security.
Nobody tells the truth all the time in life; and some people never tell the truth at all. Grown-up people involved in grown-up politics all recognize that truth is invariably rationed. The system would fall apart if it were not. But if we accept a system in which government ministers are routinely allowed to lie, then we accept a lawless system. The real question is what sort of lies can be justified.