<p> The National Labor Relations Act sets forth limited definitions of what it means to be an employer and an employee in the twentieth-century industrial economy, and bestows on the National Labor Relations Board the authority to classify employees and employers. The past half-century has witnessed the growth of triangular staffing arrangements such as franchises, independent contractors, temporary help services firms, and a service sector in which many contingent workers may not qualify as employees, leaving them unprotected by the Act. By examining Board decisions addressing joint-employer and independent contractor status since 1960, this paper has identified increased polarization&mdash;the tendency of Democratic and Republican Board members to vote in opposing, and often politicized directions&mdash;in Board decisions classifying employers and employees. The findings suggest that in determining worker eligibility for protection under the Act, the Board is more polarized than at any point in 50 years.</p><p>