A rebirth for unions? Grassroots victories and NLRB's push create new labor risk.

Only 10.3% of American workers belong to a union, and those numbers have fallen steadily over the past few decades. But organized labor has racked up some notable successes lately, often with just the local employees leading the way.

Your employees have likely taken notice--and they may be open to exploring union representation themselves. Employers need to get up to speed now on how to respond to the threat of union organizing.

You're facing another headwind in this battle. With a Democrat in the White House, the National Labor Relations Board is going all out to make the organizing climate as pro-union as possible. Over the past six months, union representation petitions filed at the NLRB have jumped 57% from the same time a year ago.

The NLRB's latest move: It wants to make it unlawful for employers to host "captive audience" meetings with employees to explain the downside of creating a union (see below).

The Amazon game-changer. One lawyer called last month's first-ever union election victory of an Amazon warehouse "the biggest workplace story of the year by far." Since then, employees at more than 100 Amazon facilities have taken steps to unionize their workplaces.

Why this matters: It could illustrate a workplace power shift. That organizing campaign at Amazon's Staten...