People think the First Amendment exists, but if you're in a labor union, the courts have declared it doesn't apply. Take union pickets-- in what is a depressingly normal decision, the Eight Circuit Court of Appeals has allowed a company to move forward on a lawsuit against a union for exercising free speech-- free speech which can be punished because it's done by a union.
The case involves an electrical company, Ruzicka Electric, which was hired in February 2001 as a contractor to help build a student center at Lindenwood University in St. Charles, Mo. The union decided to picket the university, arguing that Ruzicka Electric pays substandard wages. In response to the union picketing, a number of unions working for contractors other than Ruzicka Electric refused to go to work at Lindenwood.
And therefore, according to the decision of the Eight Circuit (and the Supreme Court), the union will have committed a crime if they asked for help as the company claims. As the court said in its decision:
The picketing will be unlawful if there is an expectation or a hope or a desire that employees of the secondary employer will be induced or encouraged to take concerted action to quit working behind the picket line...Ruzicka Electric presented evidence that Local 1 agents, acting as observers at the neutral gate, engaged in picketing activity, asking neutral employees to refuse to work. If believed, this evidence establishes Local 1 engaged in unlawful secondary activity.
Most progressives don't fully understand that if a union asks other workers to help them during a strike, they have often broken the law. That act of speech-- asking for help -- is an illegal act.
You hear people prattle on about American Exceptionalism-- that US workers are individualists and company-oriented, which is why we don't have broader labor unity or general strikes as you often see in European countries.
The answer is far more prosaic. In the US, the First Amendment has been declared null and void at the workplace door and any attempt to ask for labor unity is a crime.
It's really hard to have broad-based unity when you can't ask for it without finding yourself in court.