In Seattle this week, it's déjà vu all over again.

Four years ago, labor disputes with its employee labor unions -- first the machinists' union, then the engineers' -- brought Boeing (NYSE:BA) to the brink of ruin, threatening to derail the company's vaunted 787 Dreamliner project. Four years later, one of the contracts so laboriously negotiated back then has expired, and the parties are back at the negotiating table.

Or rather, they were at the negotiating table. Yesterday, Boeing walked out.

Taking our ball (and our money) and going home
Boeing and its engineers union, the Society of Professional Engineering Employees in Aerospace, or SPEEA, began a second round of negotiations over a collective labor agreement Tuesday. It didn't go well.

Boeing, having raised its initial salary offer to include 3.25% annual raises for technicians, and 4.25% for professional engineers, seemed nonplussed by SPEEA's counteroffer of an increase to 6% average raises for both classes of employees. (The union's previous contract codified 5% annual wage hikes). For three days, the parties sat in a room together, making little or no progress. Then, on Thursday, Boeing called a halt to the whole thing.

He said, SPEEA said
As SPEEA described the scene Thursday: "Boeing rejected SPEEA wage proposals without providing a counterproposal [and] ... restated their belief that technical workers and engineers are overpaid." Then, all of a sudden: "[The] Boeing Company stopped negotiating and recommended a federal mediator be brought in to assist our talks. The Boeing team then packed up and left."

Boeing sees things a bit differently. For example, according to the company's official website on the SPEEA negotiations, Boeing says it "explained the salary increase pools proposed by SPEEA for both the professional and technical units of 6 percent a year for three years would move the salaries of our employees above the Puget Sound market." Which sounds more like a warning that SPEEA's demands for future wages would result in Boeing employees becoming overpaid, rather than an insulting accusation that the workers were already getting more than they're worth.

According to Boeing, its "total compensation package ... already leads the market," and the company says its intent is "to improve upon" that package even more -- just not so much more as to make the company's cost structure uncompetitive. Thus, it appears there's still room for negotiation here. If taken at face value, Boeing's assertions seem to express a willingness to sweeten the deal, if only to a point.

Where to from here?
And yet, one thing doesn't appear to make sense: If Boeing says it's willing to negotiate, why isn't it? One thing both sides agree on from Thursday's meetings is that in the middle of the meeting, Boeing called for a federal mediator to intervene in the talks, and walked out without scheduling a date for the next meeting. This action hardly seems to match Boeing's words.

Be that as it may, here's where we stand today: Boeing says it wants to bring in the Federal Mediation and Conciliation Service to "help move the two sides toward a resolution." SPEEA says it will "almost certainly agree to some type of mediation."

And if that fails?
But at the same time, the risk of a crippling labor strike has become more apparent. While prepared to continue talks, SPEEA also says it has begun holding picket captain training sessions for its workers, preparatory to ordering a strike. In labor circles, this is tantamount to "calling up the reserves" and mobilizing for war. All that remains now is for a formal declaration to be issued -- for SPEEA to call a vote of its members, and authorize a work stoppage.

Thus, both sides have moved one step closer to the brink this week. Boeing, by rolling back the benefits it offered the workers last time around, offering a much slower pace of wage increases initially, and only later upping its offer to... a still slower pace of wage increases. The union, by eyeballing Boeing's "unprecedented success in profits and orders" ($4.3 billion in trailing profits -- Boeing's best profits haul ... ever!), and demanding a bigger piece of the pie, even in the face of a slow global economy and the risk that Boeing's orders might evaporate if the economy slows further.

What's it mean to you?
As the negotiations move into mediation, it's important for investors to keep an eye on what's at stake here for us. For Boeing shareholders, obviously, a work stoppage threatens approximately $250 million in daily revenues that will go uncollected, every day that Boeing planes don't get built.

But it's not just Boeing shareholders at risk. Every Boeing that doesn't get built means multiple General Electric (NYSE:GE) engines that don't get built (or paid for) either. It means fuselage sections that Spirit AeroSystems (NYSE:SPR) doesn't put together. Passenger seating that B/E Aerospace (NASDAQ:BEAV) never assembles. Lighting systems that Honeywell (NASDAQ:HON) doesn't get to produce.

This problem's bigger than Boeing, and the longer the talks drag out, the bigger it gets.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.