Case law involving legal issues surrounding labor unions can be found legal databases such as Westlaw or LexisPlus. To get started researchers can navigate to Labor & Employment Cases (Westlaw → Cases → Cases by Topic → Labor & Employment Cases). Then, conduct a key word search to find labor & employment cases concerning labor unions. 

Landmark Cases

HeinOnline's Labor & Employment research guide compiles a helpful list of landmark labor law cases. Some key cases include:

National Labor Relations Board v. Jones & Laughlin Steel Corporation, 301 U.S. 1 (1937) 

Congress has the power under the Commerce Clause to regulate labor relations. Upheld the constitutionality of the National Labor Relations Act (Wagner Act). Westlaw 

National Labor Relations Board v. Mackay Radio & Telegraph Co., 304 U.S. 333 (1939)

Employers can replace striking workers permanently during and economic strike if the strike did not involve unfair labor practices. Westlaw

National Labor Relations Board v. J. Weingarten, Inc., 420 U.S. 251 (1975)

Employees have the right to have a union representative present during an investigative interview that could lead to disciplinary action. Established so-called "Weingarten Rights." Westlaw

Adjudicatory Decisions 

Researchers should keep in mind that the NLRB is an adjudicatory agency, and should look to agency decisions in their research as well. These cases can be found on Westlaw as either Administrative Law Judge Opinions or Board Opinions. Follow the links to get started down either research path and narrow the search using key words. Cases can also be found on the NLRB website under Case Search.