During the past decade or two, a convention has started to develop that, except in an emergency, major foreign policy interventions must be pre-approved by a vote in Parliament. The idea springs from honourable motives and it is understandable given the present climate of distrust in politics, but in my judgment it is nevertheless a serious mistake … It is a basic purpose of Parliament —above all, of this Chamber—to hold the Government to account for their actions. It is for the Government, with all their advantages of preparation, information, advice and timeliness, to act, and it is then for this Chamber to scrutinise that action.
If Parliament itself authorises such action in advance, what then? It gives up part of its power of scrutiny; it binds Members in their own minds, rather than allowing them the opportunity to assess each Government decision on its own merits and circumstances; and instead of being forced to explain and justify their actions, Ministers can always take final refuge in saying, “Well, you authorised it.” Thus, far from strengthening Parliament, it weakens it and the Government: it weakens the dynamic tension between the two sides from which proper accountability and effective policy must derive.
A interesting discussion with UK Parliamentary oversight compared to Presidential oversight and some dangers of the US system.