Answer:
The United States asserted itself as an independent nation was through the adoption of the Monroe Doctrine. This doctrine came after its independence from the British and was a warning to other European countries to stop their interference in the country.
This was a major statement of the United States to the rest of the world in it being strong enough to make decisions which are in the best interest of the country.
This is of course subjective, but two of the most important civil liberties are the right to free speech and the right to practice any religion. Many would argue that access to free healthcare and free education at all levels (including college) should be civil liberties as well.
