More than 30,000 machinists could vote today on Boeing’s latest contract proposal. At stake is production of the 777X aircraft, which Boeing threatened to move out of Washington State when machinists rejected the initial labor contract. And while it might sound crazy to potentially vote yourself out of a job, the stakes are high all around.

Under the revised deal, machinists would get an extra bonus and a few other concessions. But Professor Leon Grunberg of the University of Puget Sound says their biggest concern remains: “Losing the guaranteed pension that they had,” he says. “One of the few last remaining blue collar workers in the private sector that have these guaranteed pensions.”

In fact, the local union didn’t push for today’s vote; the union’s international leadership did. It doesn’t want to risk losing thousands of union jobs to a “right-to-work” state.

Aviation industry consultant Scott Hamilton says that’s a definite possibility, though moving is risky for Boeing too. He says that, in its request for proposals, Boeing asked competing sites to basically replicate its Washington facilities, to the tune of ten billion dollars.

“I don’t see any state in the union that has the ability to go out and write ten billion dollars worth of checks to build buildings,” Hamilton says.

There’s also the risk of delay. Boeing wants to bring the 777X to market in 2020, which might not happen if it has to start from scratch.