Why do some strikes last so long? At heart, contract talks are tests of economic power. Strikes drag on when one side or the other doesn’t want to admit that the power equation has shifted.

That dynamic helps explain why it took six weeks for Ford and the United Auto Workers union to reach Wednesday’s tentative agreement. Management needed time to concede that in 2023, power has tilted to labor in many industries, partly because of a worker shortage and the ravages of inflation.

That pattern was set early this year. In March, Delta Air Lines pilots won a new contract with a 34% raise. In August, UPS workers ratified a contract that hiked minimum starting pay by 30% for part-time drivers and moved thousands of shift workers into full-time employment. In both cases, just the threat of a strike convinced the companies to open their pocketbooks.

This month, a three-day walkout by 75,000 Kaiser Permanente workers brought a 21% raise in a tentative labor contract.

Not all industries are the same. Film and TV writers spent nearly five months on the picket line – five days short of the record – to wring important concessions from Hollywood studios on new issues, such as revenues from internet streaming and limits on the use of artificial intelligence. A recordlong actors strike is ongoing with talks that restarted this week.

If ratified by union members, the new Ford contract would mean a 25% raise across the board. For low-paid temporary workers, who will now be brought on as full-time employees, the contract would boost pay by 150%. General Motors and Stellantis are expected to reach similar settlements in the coming days.