In what some attorneys are calling the most significant change in federal labor law in a half-century, the National Labor Relations Board has issued new rules that put employers in the onerous position of being forced to recognize and bargain with a union—unless they take swift action to request an employee election and prevail in that election.

“These changes radically shift the legal landscape for companies,” Morgan, Lewis & Bockius wrote in a note to corporate clients, and “make it much easier for unions to organize.”