President Ronald Reagan's showdown with the Professional Air Traffic Controllers Organization began a 30-year decline in the use of union strikes.

In August 1981, the union of government employees who guided plane travel called a strike for better pay and working conditions. Mr. Reagan, citing a federal law that prohibits strikes by government unions, ordered them back to work. More than 11,000 PATCO members defied the order. Mr. Reagan fired them.

The showdown in Mr. Reagan's first term had a big effect on unions and employers. In 1981, unions called 145 major strikes, according to the Labor Department. In 1982, there were 96 major strikes. Strikes continued to decline as globalization made it increasingly difficult for workers, particularly in manufacturing, to sustain lengthy walkouts. In 2010, there were 11 major strikes, up from five the year before.

—Joseph B. White