These MP's can then create or amend Bills in Parliament. This then alters the constitution and keeps it up-to-date with a changing society which is democratic.
The UK constitution is said to be flexible as it is unwritten. Acts can be passed through Parliament with a majority vote, new conventions may be created by a change in habitual pattern in behaviour and judges have the ability to interpret the law (case/common law). As there is no written constitution, the flexibility of it may be seen as undemocratic because even though it is a broad set of principles outlining the structure of the system it is able to change to suit any political system e.g. an extremist political party may get into power and pass undemocratic laws an they would be able to this as there is no constitution outlining the rules. .
The American constitution is said to be less flexible than that of the UK as it is very hard to amend which is shown as only 27 amendments have been made since its creation in 1787. To change the constitution a 2/3 majority is needed in both houses of Congress and ¾ of state legislature must ratify it. The Founding Fathers deliberately made it difficult to alter the constitution to preserve political stability. This method is seen as democratic as Congress is an elected body. Some people argue that the US constitution is not as rigid as it appears because firstly you can amend it and secondly the constitutional rights were written broadly which allows the Supreme Court to interpret them with relevance to the change in society.
In the US the executive branch of government which implements the law consists of the President who coordinates bureaucracy. The Founding Fathers chose a president as opposed to a monarchy when writing the constitution as they wanted a republican and democratic government. The US constitution outlines the roles, powers and limitations of the president e.