In March 1970, 250,000 postal workers went out on strike because Congress was refusing to enact legislation that would give them a long overdue raise. Many postal workers were then receiving welfare to supplement their extremely low wages. At the time, Congressional legislation was the only way that postal workers could get a raise, but because of Congressional wrangling over the structure of the Postal Service, action on postal wages was stalled.
https://prospect.org/article/how-make-sure-federal-workers-wont-go-unpaid-ever-again
