Warning strike

In the context of organized labor, a warning strike is a temporary, brief work stoppage in the course of the collective bargaining process.^[1]

Lasting a few hours or up to a day, it serves to signal the union's ability to mobilize through disruption of regular business, while stopping short of an indefinite strike.^[2][3][4] In some jurisdictions, a warning strike can be called by union leadership without a vote of the membership.^[1][3]

Warning strikes are most common in Germany, where they are known as Warnstreiks.^[2][5][6] They have been used frequently and to significant effect there.^[3][7] Since a 1976 ruling, the right to hold warning strikes outside the period of Friedenspflicht [de] ("peace obligation") has been protected under the Basic Law.^[1][2][8]

They have also played an important role in Poland, where they are known as strajki ostrzegawcze.^[9] Notably, the four-hour 1981 warning strike was the largest strike in the nation's history, with as many as 14 million Poles participating, making up almost the entirety of the working population.^[10][11][12] Today, warning strikes are permitted under the 1991 Trade Union Act but are limited to 2 hours in length.^[1]

Occasional warning strikes have also occurred elsewhere, such as in South Africa, Nigeria, and Israel.^[13][14][15] In the United States, the National Labor Relations Act does not permit a series of short, interrelated strikes, but one short warning strike followed by an indefinite strike is allowed.^[16]