There is a fundamental conflict between labor law and antitrust law. The antitrust laws reflect the powerful idea that competition should usually dictate the way our economy is organized, to the benefit of the economy as a whole, including workers. But the labor exemption to the antitrust laws suggests a different policy: workers should have the right to eliminate competition for wages, hours, and working conditions.
Reducing Unions' Monopoly Power: Costs and Benefits, 28 J.L. & Econ. 297 (1985)