Where does the power lies within representative democracy?

Representative democracy (also indirect democracy, representative republic, or psephocracy) is a type of democracy founded on the principle of elected officials representing a group of people, as opposed to direct democracy.[2] Nearly all modern Western-style democracies are types of representative democracies; for example, the United Kingdom is a constitutional monarchy, Ireland is a parliamentary republic, and the United States is a federal republic.[3]

Representative democracy is often presented as the most efficient form of democracy possible in mass societies. It arguably allows for efficient ruling by a sufficiently small number of people on behalf of the larger number. Government efficiency can be judged based on metric of cost effectiveness and time effectiveness. Representatives voting on behalf of the people allows for a monetary benefit as there is lessened use of polling stations, vote counters, etc. The government is generally responsible for paying for the wages of the representatives and would have to cover the substantial cost of a direct democracy. This system of governance is also time efficient as decisions can be made by a select few, knowledgeable group of legislators rather than the entire country's population.[3] Representative democracy has conceptually associated with and historically instantiated by the political system known as "representative government", which was born in the 18th century with the French and American revolutions. It is a system in which people elect their lawmakers (representatives), who are then held accountable to them for their activity within government.[4]

It is an element of both the parliamentary system or presidential system of government and is typically used in a lower chamber such as the House of Commons (UK) or Dáil Éireann (Ireland), and may be curtailed by constitutional constraints such as an upper chamber. It has been described by some political theorists including Robert A Dahl, Gregory Houston and Ian Liebenberg as polyarchy.[5][6] In it the power is in the hands of the elected representatives who are elected by the people in elections.

whitch constitution would be inadequate as a basis for government today?

the answer would be a) it only allowed catholics to be in government.

answer; software failure, and human error;