Last December the new Republican majority National Labor Relations Board weakened an Obama-era board decision allowing unions to organize small groups of a workplace’s total workforce, called “micro unions.”

One of those campaigns lingering from the previous era show how useful that tool has been for unions when, out of a workforce totaling about 6,800 at Boeing’s plant in Charleston, SC, a group of 178 technicians voted in favor of being represented by the International Association of Machinists and Aerospace Workers.

The vote allows IAM to get a foot in the door in a plant where it had failed massively last year, when a much larger group of employees voted overwhelmingly against union representation, creating nationwide headlines. It was the machinists’ third attempt to organize Boeing workers at its only jetliner assembly plant outside Washington state, where the company is based.

David Pryzbylski, an attorney with the law firm of Barnes & Thornburg, said, “This case will be important to watch as it continues to unfold, and it serves as a reminder that employers must continue to evaluate how to stave off potential micro-unit determinations at any sites where they may be vulnerable to union organizing attempts.”

Asserting that the micro unit was “an artificially gerrymandered sub-set of employees,” Boeing asked the NLRB in May to stop the vote from taking place.

However, the planned vote was allowed to go forward by one of the NLRB’s regional directors – a decision the board upheld. For its part, Boeing said it would appeal the board’s ruling.

However, over the years the board has generally been reluctant to reverse these kind of organizing votes once the election has been certified.