In the 18th century Liberalism help in the American Revolution by challenging the Absolute power of the Monarchy. (Political Ideologies p.24, 25) Liberalism were tired of the notation of "divine rights of a king" and an "accident of birth" for the social class statuses. Liberalism pushed for a government of representation and constitution, which is the opposite of Monarchy.
In the United States the Declaration of Independence is a liberal idea. It state that all men are crated equal, have the rights to life, liberty and property. (The US Constitution p. 59) Declaring ones independence is an act of rebellion, which is self an act of one liberty. The US Constitution followed the Declaration of Independence in 1778, it was written by James Madison the "father of the Constitution". (The US Constitution p.6) The US Constitution is a liberal document. One reason why is the separation of branches, it limit the power of all three branches, by a system of "checks and balances". (The US Constitution) .
The19th century was a goriest time for liberalism, the US's Constitution add new additions with the Bill of Rights which has liberal values. Under the Bill of Rights are civil rights are protected. Example would be the 1st amendment the right to religion, speech, assembly petition and press. (The US Constitution p. 45) These rights give us the liberties to openly/publicly speck our minds, without the worry of being kill for it. .
The US's Constitution adds in the 13th, 14th, and the 15th amendments that free all men to have liberty, nor was it limited to just white men 21 year old land owners. With these additions black men were free to work for who they wish, vote, and own land without the state taking it away without due process. (The US Constitution p. 49) .
The early Liberalism can founded in the writing of Thomas Hobbes's Leviathan, John Locke's Two Treatises on Government, and Adam Smith's The Wealth of Nations.