In November, two-thirds of machinists voted against a similar offer that would have replaced their traditional defined-benefit pension with a 401(k)-style savings plan, one of two retirement plans the workers receive.
The union's national leadership negotiated that deal, which would have extended the contract eight years beyond its current expiration in 2016. But local leaders opposed it, saying the take-aways were too great.
Now, the same dynamic is playing out again. Boeing has sweetened the offer with a larger signing bonus and other changes. But the deal still eliminates the pension, and local union leaders have urged members to reject it.
"You need to look at the facts of the economic destruction you would live under for the next 11 years," local leaders said in a letter to members.
The national leaders say the new offer is $1 billion better than the prior one.
"The membership deserves the final say," said R. Thomas Buffenbarger, president of the IAM International, which also has members in Canada.
The issue has drawn wide attention as other states bid to win thousands of well-paid jobs and because of the tactics Boeing has used to bargain with its union.
Even noted consumer advocate Ralph Nader has weighed in, calling Boeing's tough stance "unseemly," given Chief Executive Jim McNerney's $21 million pay package.
"A book could be written about the Boeing company's strategy for externalization of a variety of its costs onto innocent, defenseless people—whether workers or taxpayers," Nader wrote.
Beside the pension loss, local union leaders say the language of Boeing's offer does not ensure that machinists will get the work, because it reserves Boeing's right to use lower paid contractors.
"I'm very, very skeptical of what Boeing is saying to us," Lester Mullen, a local District 751 council delegate, said on Thursday from the shop floor where he builds Boeing's 777 wings in Everett, Washington.
Even if workers approve the contract and Boeing builds the 777X in Washington, Boeing could outsource the work to a vendor.
"It doesn't mean we're getting the work. It just means it's going to be built here," he added.
Boeing responded this week by saying that it will establish its base for making the 777X's carbon-composite wings in the Puget Sound area, which includes Seattle.
"This work will be performed by the mechanics who currently build aluminum wings here in Puget Sound," Alan May, vice president of human resources at Boeing Commercial Airplanes, said in a letter sent to 777 workers.
On Thursday, it issued a further statement saying "current mechanics will have the opportunity to be trained for this new composite work" and noting that it would make its 737 MAX jet in the area, and do KC-46 aerial refueling jet and P-8 submarine killer jet production work, "in the Puget Sound and Portland through 2024."
The company declined to comment on Nader's letter to McNerney.
The divide between the local leaders and their national counterparts is mirrored by divisions over the contract that appear to cleave along age lines.