Libertarianism is a political ideology which asserts that freedom is the most important concept which an individual should stand for while alive. Libertarianism is a political philosophy which puts forth individual liberty and individualism over collectivism and a negative, slave-based hive mindset that a lot of people are falling for nowadays, some willingly opting for it while others doing it because they seem not to know anything else or not to know better.
The Nolan chart highlighting the political position of libertarian(ism) in its top. Image source: Commons Wikimedia
While somewhat related to liberalism, according to Encyclopaedia Britannica at least, libertarianism draws some core economic principles and civil liberties from its most earliest form (i.e. classical liberalism, as defined by English philosophers John Locke and John Stuart Mill, Scottish economist Adam Smith, or American statesman and founding father Thomas Jefferson) but campaigns for a far suppler government and a limited overall influence of authority in the everyday life of each citizen of a republic.
In other words, libertarianism can be summed up best by saying that one should not interfere with the liberty of another one and with that person's free will just as the other person in question should not interfere with the initial one. Now there are various trends, political parties, and factions of said parties within the overall libertarian political stream worldwide, but the main idea is that this political ideology/philosophy puts a strong focus on self-ownership, individual freedom, and private property, according to Stanford Encyclopaedia Of Philosophy.
Interestingly enough, on the political spectrum, there one could be a left-wing libertarian or a right-wing libertarian. If you are a conservative libertarian, then you are right-wing. According to Wikipedia, libertarianism actually originated in a left-wing movement which was quintessentially anti-authoritarian and anti-state.
The sort of niche philosophical and economic models of anarcho-capitalism and minarchism (also known as 'Night watchman state') are equally part of the libertarian movement, as they have been encompassed in it during the mid 20th century by libertarian proponents in order to broaden laissez-faire capitalism and private property rights.
To the best of my knowledge, the only major libertarian party out there is in, you guessed that right I presume, the United States of America. That is I hope correct, at least judging by the sheer number of registered party members totalling an impressive amount of 693,634 as of 2021.
The Libertarian Party is also the third largest party nationwide in the US just after the Democratic Party and the Republicans. The Libertarian Party in the US mainly promotes classical liberalism in stark contrast to the Democrats' modern liberalism or the Republicans' recent isolationist-conservative trend as expressed during the presidency of Donald Trump. The electoral symbol of the Libertarian Party is the hedgehog. In other words, some of libertarians are quite 'spiky' so you would better not tread on them if you know what's good for you... the undersigned included. :)
The Libertarian Party in the US also promotes non-interventionism and has had, since its foundation in December 1971, an anti-war agenda, being deeply concerned as such of the Richard Nixson administration's foreign policy in Vietnam. Therefore, collectively, the Libertarian Party does not want the US to be involved in any war whatsoever, which is an absolutely great and wise decision. Its slogan is 'minimum government/maximum freedom' which bids quite well to many intellectual rebels out there, myself included. ;)
So far, the best candidate that the Libertarian Party had in the US presidential elections was Gary Johnson, an ex-Republican, who won 4,489,359 votes, or 3.27%. At central political level however, while the 2020 House of Representatives and Senate elections are concerned, the Libertarians failed to obtain any seats in Washington D.C. and even lost a previous one which they won at the previous 2016 elections.
To conclude however, will libertarianism be a future strong alternative for the disappointed voters of both the left wing and the right wing parties in both developed and developing countries in the Americas and/or Europe? That remains to be seen...
As to know whether or not you are one... the decision is now yours based on what I have carefully selected, presented, and described to the best of my capabilities. Next time you vote though, regardless of what country you are in, make sure though NOT to vote for any socialist... Trust me, I know what I'm talking about. It's for your own sake, chaps!
Further documentation: What is a libertarian? on www.libertarianism.org