The constitution maybe a written document, If so, the act by which the people adopt the constitution is an act prior to the existence of government. That fact raises an interesting question about Lincoln's dating of the birth of the United States in 1776 rather than 1791, when George Washington took office as the first President of the United States. Another interesting question is whether there is constitutional government in the United Kingdom. The most important feature of constitutional governments lies in the distinction between a government of men and a government of laws. But when those who govern not by their personal power, but by the power vested in the office they hold, assigned to that office by the constitution they swear to uphold, then the government is a government of laws.
Constitutional governments can, in time, change, become less oligarchical and more democratic.
The mode of amending constitutions must be prescribed by the constitution itself. Office holders are not the governors in constitutional government, but rather the people who adopt and amend the constitution. It is they who, as citizens under the constitution, vote and elect those who administer the government. The government resides in the power of the people who have been made citizens. The officeholders in Washington and elsewhere are its administrators.