Politics is a demanding profession that calls for skills of leadership and oratory, as well as management, analysis, and even theatre. Asking a politician to be truthful as well may be looking a gift-horse in the mouth. But we do. Misleading parliament by being ‘untruthful’ (‘lying’ is so reprehensible that it is unparliamentary to accuse a member of it) is a serious offence. In the US presidential system, where the executive is independent of the legislature and the head of government is also head of state, the great deterrent to lying is the authority that Congress has to censure and expel its members and to impeach officials, including the president.