James Damore, the Google engineer fired over an essay he wrote criticizing the company's diversity policy, will face an uphill battle arguing that his dismissal was illegal under the National Labor Relations Act, the main federal law covering union activity, legal experts note.

However, the software engineer's argument to the National Labor Relations Board that his memo was a discussion of workplace conditions covered by the NLRA isn't crazy either, especially since the law was significantly broadened during the Obama administration.

The question before the board, which enforces the NLRA, is whether the memo amounts to what the law terms "concerted, protected activity." That is, was Damore attempting to engage employees in an effort to improve their working conditions at Google? The board has long used a broad definition of what the term "activity" means, expanding it in recent years.

"If it is true that he had discussions with his coworkers about the memo and this extended to talking about the working conditions at Google and the company was aware of these discussions, if these two factors were present, then he may have a case," said Steve Bernstein, a labor law attorney with the management-side firm of Fisher & Phillips.

That appears to be what Damore is arguing in a complaint filed with the NLRB. Damore was fired by the tech giant Monday after a 10-page memo he wrote became viral on the web. In the essay, Damore argues, among other things, that "differences in distributions of traits between men and women may in part" explain disparities in hiring and pay between genders in the technology industry and called for "an open and honest discussion about the costs and benefits of our diversity programs." Google said it fired him because he "advanced incorrect assumptions about gender."

On its face, his filing seems a stretch since the labor relations act mainly covers labor-related activity and neither Google nor Damore have said he was agitating to form a union. However, the law is much broader than that, notes Joshua Parkhurst, a New York-based labor lawyer who represents workers.

"The NLRA isn't just about unions. It covers and protects all workers," Parkhurst said, noting that any activity that involves a worker engaging with other employees regarding their working conditions is potentially covered by the law.

In an interview Tuesday with podcaster Stefan Molyneux, Damore said, "I did share the document multiple times a month ago and many people looked at it but no one had this explosive reaction. All of the responses were just rational discussion."

He reiterated that argument in an essay posted Friday on the Wall Street Journal website. "When I first circulated the document about a month ago to our diversity groups and individuals at Google, there was no outcry or charge of misogyny. I engaged in reasoned discussion with some of my peers on these issues, but mostly I was ignored," he wrote.

Damore's NLRB complaint said the company violated his rights by "threatening employees because of their concerted protected activities" as well as "making threats of unspecified reprisals" for those activities.

Wilma Liebman, a former chairwoman of the labor board, said Damore's claims "gets him closer to arguing it was protected because he says he was engaging with other people at work. The question is whether Google knew this." If he can prove the company did know, then he has a case, she said.

Parkhurst nevertheless calls the case "a stretch ... borderline frivolous." He adds that under anti-discrimination laws, the company was pretty much obliged to fire Damore since his memo could be cited by other employees in sex-discrimination cases. "As an attorney in a discrimination case that is the type of proof you would look for," he said.

However, the NLRB has found that offensive comments by employees don't necessarily cancel out their protections under the NLRA. In the 2016 case Cooper Tire and Rubber, the board ordered a manufacturer to pay restitution to the employees it fired because they shouted racial epithets at replacement workers who crossed a picket line. The decision was recently upheld by the 8th Circuit Court of Appeals.

Liebman said it remains a question when exactly speech becomes so egregious that it creates a hostile workplace. "It may be a stretch to say this is protected activity but it isn't an open and shut case that it isn't either," she said.