When is it okay to for a Starbucks employee to use profanity within earshot of customers? You might say never, but a National Labor Relations Board has ruled that the coffee colossus was in the wrong for firing a worker for dropping some R-rated words when involved in pro-union protest.

This particular case, involving an employee at a Manhattan Starbucks, goes back almost ten years to 2005, when the worker — already identified by management as an active member of a pro-union movement at the store — got into an argument with his manager.

Angry that the manager had not come out to help during an especially busy period, he apparently lost his temper when the manager did come out, saying it was “about damn time,” then noisily shoved a blender in the sink. He also told the manager “this is bullsh*t,” and to “do everything your damn self.”

This resulted in a brief suspension and a written warning that repeat occurrences would “result in termination of employment at Starbucks Corporation.” The employee says he never actually received this warning.

Several months later, the employee and other workers protested a District Manager’s order against wearing pro-union pins by showing up at the store during their off-work hours and sporting the forbidden pins.

This led to a confrontation with an off-duty assistant manager from another store who was at the location at the time. The employee claims this particular assistant manager had previously made derogatory comments to the employee’s father who was a vocal pro-union supporter and who the manager had allegedly confronted while handing out union-related leaflets at a Starbucks event.

So the employee asked the assistant manager about the things that had been said to his father. This sparked a loud argument, during which the employee told the off-duty manager, “You can go f*ck yourself, if you want to f*ck me up, go ahead, I’m here.”

The on-duty manager — the same one involved in the earlier blender-shoving incident — was among those who intervened to bring an end to the dispute. The employee and his fellow protestors remained in the store for about another 10 minutes with no further incidents and no police being called.

A few weeks later, the employee was fired for disrupting business in the store during the protest. A document filed by the store manager claimed that the employee “was insubordinate and threatened the store manager,” and that he “strongly support[ed] the IWW union.”

In 2010, following the ruling of an administrative law judge who found that Starbucks had violated Section 8(a)(3) and (1) of the National Labor Relations Act, which deal with employers who inhibit workers’ rights to protest.

The NLRB found that the employee was engaged in protected, concerted activity during his argument with the off-duty assistant manager, and that his statements were not egregious enough to merit dismissal.

However, a U.S. Circuit Court of Appeals later found that the NLRB had “improperly disregarded the entirely legitimate concern of an employer not to tolerate employee outbursts containing obscenities in the presence of customers,” saying that the legal precedent used to defend the worker’s outburst was intended to protect workers from being retaliated against for using profane language in closed quarters like an office or factory floor, not a very public storefront.

The court sent the case back to NLRB to decide what standard should apply when an employee, “while discussing employment issues, utters obscenities in the presence of customers.”

In its review of the case [PDF], the NLRB ruled that, even if you assume that the public nature of the employee’s outburst strips him of the protections afforded by the NLRB Act, the manager’s documented statement that he was being fired — and could not be considered for re-hiring — because of his support of the union, demonstrates that his dismissal was at least partially motivated by his pro-union leanings.

The NLRB also found that, given Starbucks’ “more lenient treatment of other employees who engaged in similar or worse misconduct that… occurred in the presence of customers,” the company did not prove that it would have fired the employee for this outburst alone.

For example, the ruling points out that the off-duty assistant manager involved in the argument was not disciplined by Starbucks, despite evidence that he both provoked the incident and used profanity within earshot of customers.

The Board has ordered Starbucks to offer the fired employee his old job back and to compensate him for loss of pay and benefits.