Because of differences in their written constitutions, the formal powers of monarchs, governors-general, and presidents vary greatly from one country to another. However, as sovereigns and governors-general are not elected, and some presidents may not be directly elected by the people, they are often shielded from any public disapproval stemming from unilateral or controversial use of their powers. In many Commonwealth realms a governor-general formally represents the monarch, who is usually absent from the realm. In such countries, the identity of the "head of state" may be unclear. In the book "The English Constitution", Walter Bagehot emphasised the divide of the constitution into two components, the Dignified (that part which is symbolic) and the Efficient (the way things actually work and get done), and called the Efficient "Cabinet Government". Although there have been many works since emphasising different aspects of the "Efficient", no one has seriously questioned Bagehot's premise that the divide exists in the Westminster system. Members of the Cabinet are collectively seen as responsible for government policy, a policy termed cabinet collective responsibility. All Cabinet decisions are made by consensus, a vote is rarely taken in a Cabinet meeting. All ministers, whether senior and in the Cabinet, or junior ministers, must support the policy of the government publicly regardless of any private reservations. When a Cabinet reshuffle is imminent, a lot of time is taken up in the conversations of politicians and in the news media, speculating on who will, or will not, be moved in and out of the Cabinet by the Prime Minister, because the appointment of ministers to the Cabinet, and threat of dismissal from the Cabinet, is the single most powerful constitutional power which a Prime Minister has in the political control of the Government in the Westminster system. The Official Opposition and other major political parties not in the Government, will mirror the governmental organisation with their own Shadow Cabinet made up of Shadow Ministers. In a Westminster system, some members of parliament are elected by popular vote, while others are appointed. Nearly all Westminster-based parliaments have a lower house with powers based on those of the House of Commons (under various names), comprising local, elected representatives of the people (with the only exception being elected entirely by nationwide Proportional Representation). Most also have a smaller upper house, which is made up of members chosen by various methods:  In the UK, the lower house is the de facto legislative body, while the upper house practices restraint in exercising its constitutional powers and serves as a consultative body.