"The process of collective bargaining, as usually understood, cannot be transplanted into the public service."

FDR wrote in 1937, quoted by Real Clear Politics:

Yes, public workers may demand fair treatment, wrote Roosevelt. But, he wrote, "I want to emphasize my conviction that militant tactics have no place" in the public sector. "A strike of public employees manifests nothing less than an intent on their part to prevent or obstruct the operations of Government."