Detroit’s automakers have rebounded since the dismal days of 2009, when Washington steered General Motors and Chrysler through bankruptcy proceedings on the taxpayers’ dime. Sales of cars and light trucks have slowed slightly recently, but they are still expected to hit 13 million this year, up from 10 million in 2009. The carmakers posted a combined profit of $6 billion in the first quarter of the year.

This week, the automakers kicked off the first round of contract negotiations with the United Automobile Workers since the government bailout. Both sides seem serious about finding a reasonable compromise. We hope that attitude survives as the parties stake out their positions.

While the U.A.W. must refrain from extreme demands, Detroit’s automakers must remember that their rebound would not have been possible without deep concessions by the union. It is time for them to start giving back to their workers.

In the last contract talks four years ago, the union agreed that newly hired workers would earn about half the $29 an hour made by the existing work force. As car sales plummeted in 2008, the unions made further concessions, including giving up cost-of-living increases, dental coverage and the “jobs bank” that allowed laid-off workers to keep drawing most of their wages.