parliamentary systems require ministers to serve in parliament, while others ban ministers from sitting in parliament (they must resign on becoming ministers). Removal Heads of government are typically removed from power in a parliamentary system by Resignation, following: Defeat in a general election. Defeat in a leadership vote at their party caucus, to be replaced by another member of the same party. Defeat in a parliamentary vote on a major issue, e.g., loss of supply, loss of confidence. (In such cases, a head of government may seek a parliamentary dissolution from the head of state and attempt to regain support by popular vote.) Dismissal — some constitutions allow a head of state (or their designated representative, as is the case in some Commonwealth countries) to dismiss a head of government, though its use can be controversial, as occurred in 1975 when then Australian Governor-General, Sir John Kerr, dismissed Prime Minister Gough Whitlam in the Australian Constitutional Crisis. Death — in this case, the deputy head of government typically acts as the head of government until a new head of government is appointed. First among equals or dominating the cabinet? Constitutions differ in the range and scope of powers granted to the head of government. Some older constitutions; for example, Australia's 1900 text, and Belgium's 1830 text; do not mention their prime ministerial offices at all, the offices became a de facto political reality without a formal constitutional status. Some constitutions make a Prime Minister (first among equals) and that remains the practical reality for the Prime Minister of Belgium and the Prime Minister of Finland. Other states however, make their head of government a central and dominant figure within the cabinet system; Ireland's Taoiseach, for example, alone can decide when to seek a parliamentary dissolution, in contrast to other countries where this is a cabinet decision, with the Prime Minister just one member voting on the suggestion. In Israel, while the Government is nominally a collegiate body with a role for the Prime Minister, the Israeli Prime Minister is the dominant figure in the executive branch in practice. The Prime Minister of Sweden, under the 1974 Instrument of Government, is a constitutional office with all key executive powers either directly at his or her disposal or indirectly through the collegial Government, whose members are all appointed and dismissed at the Prime Minister's sole discretion. Under the unwritten British constitution, the