Tax protesters, not to be confused with tax resisters.

Tax resisters refuse to pay taxes based on the personal belief that the current government is unethical and accept consequences of their actions. It included many respected figures in history from various political camps, such as anarchists, abolitionists, or pacifists. On the other hand, "tax protesters" are an uniquely American concept - it rejects taxation not from an ethical or ideological point of view, but from a legal point of view. There are various versions of this type of conspiracy theory, they basically claim that...

1. Within the political system of the current government, the government has no power to collect taxes, paying taxes is not mandatory, a personal income tax is unconstitutional, etc.

2. It's also possible to force the government to acknowledge this fact by using the court system for judicial review.

Of course, their so-called evidences are numerous references to misunderstood legal code - reinterpreted with no regards of its correct context. This line of thinking is totally absurd, tax protesters are basically libertarians who believe the existence of magic. While I might respect an authentic libertarian who refuses taxes from an ideological perspective, I have no respect for "tax protesters".

There also exists "Sovereign Citizen", "Freeman on the Land", etc, which are basically more extreme versions of the same pseudolegal conspiracy theorists. The RationWiki (which is a biased source, but totally adequate to explain this topic) has a good summary [0][1]. The core beliefs are the same - that the power of the State is illegal according to the State's own laws, and that you can actually challenge the State by using its own legal system. However, in the Sovereign Citizen's theory, the story is the following:

1. The contract laws are the most powerful laws and even the power of the State comes under it, because its power is derived from the Anglo-Saxon Common Law system.

2. Thus, being governed by the State is actually established by a voluntary contract.

3. However, in order to rule you, the State keeps tricking you to accept its evil contracts without your knowledge - a court order, a driver's license, a passport, a parking ticket, etc, are actually disguised contracts that put you under the power of State.

It's claimed that by knowing these "truths", you can free yourself from these contracts, thus also free yourself from the power of the State. For example, by not getting a driver's license and refusing to accept a court order (which brings serious troubles to you). And finally, by learning some pseudolegal terminologies (basically magic spells), you can make the court to acknowledge it and officially free yourself from the State. Yeah, the Sovereign Citizen legal theory is almost like the plot from Faust or its magical-girl anime adoption, but even better, with the possibility of opting out from the contract later on! No need to say more...

BTW, this is only one of the possible legal conspiracy theories used by them, there are more. Another one claims that the State has power over you, only because it secretly created a corporate identity for all human citizens, and most laws only have power over the corporate identity (written in all caps), not your personal identity. By knowing some pseudolegal magic spells (e.g. writing your name as "Flesh and Blood Human, John Random, from the family of Hacker" with a bloody fingerprint [2]), you can distinguish the two identities in legal documents, enabling you to detach yourself from the corporate identity at court, thus nullifying your crimes, your debts, or most laws in existence.

[0] https://rationalwiki.org/wiki/Pseudolaw

[1] https://rationalwiki.org/wiki/Sovereign_citizen

[2] Which is believed to be the highest form of ID, owned by a human being, not a legal corporate identity.