There's no fun in stating the obvious. Sophisticated professionals bestow few kudos on those who declaim the conventional wisdom. Even so, one would have to be far more perverse than I, in this fiftieth anniversary year of the National Labor Relations Act, to suggest that the Wagner Act, wasn't the most important (and at the time of it- passage the most controversial) development in the last half-century of labor law.
St. Antoine, Theodore J. "The Wagner Act: Labor Law's Signal Event." Mich. B. J. 64, no. 8A (1985): 121-2.