"Freedom of association is the individual right to come together with other individuals and collectively express, promote, pursue and defend common interests. The right to freedom of association has been included in a number of national constitutions and human rights instruments, including the US constitution and the European Convention on Human Rights.
Freedom of association in the sense of workers' right to organize and collectively bargain is also recognised in the Universal Declaration of Human Rights and International Labor Organization Conventions.
The right to freedom of association is sometimes used interchangeably with the freedom of assembly. More specifically the freedom of assembly is understood in a political context, although depending on the source (constitution, human rights instrument etc) the right to freedom of association may be understood to include the right to freedom of assembly."
The right of free association is a fundamental human right and tyrants have always agitated against this right throughout history. It's one thing if a lone crank says something crazy, but when 10, 100 or 1,000 people start saying it together, the tyrant has a tendency to take an interest and suddenly develops the urge to disperse crowds in the name of "public safety." Cf Tiananmen Square.
As Wikipedia notes, the US Constitution and the Universal Declaration of Human Rights have acknowledged that the freedom of association is a basic human right.
But there's another freedom that's just as important, and it is the other side of the coin: the freedom of non-association. Everyone is free to not associate with persons that they do not want to associate with. Divorce, as messed up as divorce laws are and always have been, is an example of this principle in action. No man has the right to force a woman to stay in a marriage which she no longer wants to be part of for any reason, and vice-versa. This is the freedom of non-association. Marriage is voluntary and both parties must continue their consent to be married, or the marriage is dissolved.
Secession is the freedom of non-association on a political scale. No political entity has the legitimate right to force a group of people to remain in union if they do not want to be part of that political entity anymore. Interestingly, majority-rule advocates suddenly become advocates of the rights of the individual when it comes to the issue of secession... "but what about the people in the seceding territory who want to remain in the political union?" This is easily answered since the seceding political unit can have no less claim to sovereignty on the basis of the consent of a territorial majority than the territorial majority of the larger political union from which it is attempting to withdraw. Their claims to sovereignty being equal, and one unit no longer desiring to be party to the relationship, the relationship should be dissolved in accordance with the freedom of non-association.
Properties owned by the larger political unit can be handled through compensatory payment by the seceding political unit. All further entanglements can be dissolved and the seceding political unit can peacefully become its own, sovereign territory, collecting its own taxes, producing its own border defense and regulating its own money and domestic and international commerce.
The American "Revolution" was, in fact, an act of secession from the Crown. The South attempted, and failed, to secede in the war of 1861. The US Federal government with its astronomical deficits and burdensome debt and the Federal Reserve and its rampant inflation to finance the Federal debt, are saddling us with trillions of dollars of subsidies for the power elite orbiting Washington DC and the global power stratosphere. I can't tell any US state whether they should or should not secede. However, it must be understood that secession - like non-assocation - is a basic human right and that the objections of the larger political union ("You didn't get permission from 75% of the states, you can't secede!") are not valid so long as a majority of the population in the seceding territory want out.