There's a word in the very first line of the Constitution of the United States that describes the instrument through which freedom is held. It's a term for people acting in concert to secure their liberty and hold those rights against any opponent. That word is union.

From its founding, the story of this nation has been the story of union. It is the story of two centuries spent in building up the ability of ordinary citizens to treat with wealthy, powerful, politically connected entities. That story contains instances of tragedy. Thousands died in the struggle, many thousands more suffered poverty or were outcast from communities. But the story of union also contains far-reaching triumphs. Every paid vacation, every weekend, every overtime dollar, every protection from arbitrary dismissal and unfair treatment, everything that makes your working life tolerable, came because people stood together in union at risk to their own livelihoods and often their own lives. Some of those laws exist only because workers stood in union when not only corporations but their own government attacked them not just with guns, but with bombers. They paid the price. You reap the benefits.

When we talk about "the greatest generation" that brought the nation through World War II and built America into a post-war powerhouse, we're speaking of a population where nearly a third of workers were union members. It's no coincidence that the peak period of growth and progress coincides with the peak period of union membership. When people act in union, there's nothing they can't accomplish. When people cannot join in union, when everyone must face the powerful alone, all rights are nothing more than words.

Whether in a union of states and nations or a union of workers and citizens, only by working in concert can rights be wrested from oppressors and held against despots. That's why tyrants quake at the sound of union. That's why the right to act in union is the ability that the downtrodden most desire and authorities first attack. Union is the measure of freedom.

The outlawing of independent unions is the clearest and most consistent marker of despotism around the world. When Gaddafi seized control of Libya in 1969, his first speech proclaimed the end of labor unions. No sooner had he secured control of Cuba than Fidel Castro banned the ability of unions to strike or to bargain over salary and benefits, saying such demands were detrimental to "the national economy." In Colombia today, right-wing militias work together with corporations to keep down costs and demands for decent working conditions in the most effective way they know–they execute union leaders.

There's a good reason why governments and corporations alike show trepidation when people are able to organize. Union is effective. For all the pretty speeches and all the ham-handed threats, the signal that the Iron Curtain was finally rising didn't come in Berlin or Washington, D.C., it came in the shipyards of Gdańsk, when men dared to wave the flag of an independent union. Want to determine where governments are actually concerned about the rights of their people? You only have to look at how free people are to organize for a cause. Without that, no other rights matter. With it, all other rights will follow.

The First Amendment to the Constitution enshrines a number of freedoms including religion, speech and the press, but this amendment should not be read as a random list of disconnected items. Everything in it directly depends on the liberties held out in the closing words: the ability of the people to peacefully assemble and to petition for redress. When the Constitution extends the right of assembly, it's not just giving us the right to gather together for no purpose. What's protected is the right to join together in common cause , and to seek as a group to move institutions that would not respond to individuals acting alone.

The American dream—the dream that an average citizen can enjoy a decent life, raise a family, and hope for the future—was created in union, sustained by union, and is dependent on union. That dream stands on a knife edge. Already the forces that oppose union have torn away the hopes of many Americans. As union membership has fallen, decent pensions have disappeared. As union membership has fallen, health care costs have increased. As union membership has fallen, pay for workers has stagnated. As union membership has fallen corporate profits—and executive pay—have soared. The decline of union is the birthplace of inequity.

At this moment, the same forces that have ripped union away from most workers are acting against those few who still share the ability to speak with a collective voice. They want to wreck this last bastion, burn it down, stomp it, bury it, extinguish it forever, so that they can sleep safe knowing their power will not be challenged. They want to erase the work of two centuries, turn the American dream into a subject for nostalgia, and make the Bill of Rights into a sheet of paper.

That is what's on the line in Wisconsin.

Nothing has changed since the time that first line of the Constitution was written. Union is not just a means to oppose tyranny, it is the only means.