Office of itself does much to equalize politicians. It by no means brings all characters to a level: but it does bring high characters down and low characters up towards a common standard. In power the most patriotic and most enlightened statesman finds that he must disappoint the expectations of his admirers: that if he effects any good, he must effect it by compromise; that he must relinquish many favourite schemes; that he must bear with many abuses. On the other hand, power turns the very vices of the most worthless adventurer, his selfish ambition, his sordid cupidity, his vanity, his cowardice, into a sort of public spirit. The most greedy and cruel wrecker that ever put up false lights to lure mariners to their destruction will do his best to preserve a ship from going to pieces on the rocks, if he is taken on board of her and made pilot: and so the must profligate Chancellor of the Exchequer must wish that trade may flourish, that the revenue may come in well, and that he may be able to take taxes off instead of putting them on. The most profligate First Lord of the Admiralty must wish to receive news of a victory like that of the Nile rather than of a mutiny like that at the Nore. There is therefore a limit to the evil which is to be apprehended from the worst ministry that is likely ever to exist in England. But to the evil of having no ministry, to the evil of having a House of Commons permanently at war with the executive government, there is absolutely no limit. This was signally proved in 1699 and 1700.
Lord Thomas Babington Macaulay: History of England, ch. xxiv.