After the American Revolution the United States implemented indirect democracy, a slightly more democratic version of the British Parliament. Feeling angry at monarchies, the Revolutionaries decided to have a democratically elected President and Congress. (in addition to very democratic state governments ). The American parliamentary democratic system was copied successfully by many countries worldwide including the United Kingdom. George III was totally undemocratic when he provoked the War of Independence with the Boston Tea Party. Paradoxically the world owes our type of democracy to him.
Several Founding Fathers later went on to become President of the United States. The first 3 Presidents of the United States were, George Washington, John Adams and Thomas Jefferson. During Jefferson's presidency France which had helped the United States during the Revolution needed money. Jefferson bought the USA good territory from France which more doubled the size of the new nation and improved its prospects. 
The new Democracy inspired Liberals in Europe and elsewhere. Over the centuries that followed the concept of Freedom that inspired the revolution was developed further leading later to the ending of Slavery, Women's suffrage and more.