In January, Mark Blondin, chief of Boeing's (BA

) largest union, will go before a jury to answer charges that he was drunk when his Chrysler (DCX

) 300 slammed into a Toyota (TM

) Camry on Interstate 90, east of Seattle. The accident, which happened under clear skies at 7 p.m. on Dec. 19, 2005, destroyed both cars, and sent the other driver, retired nurse Mitchell J. Alexander, to the hospital with a serious head injury. Blondin, who has pleaded not guilty to criminal charges of drunk and reckless driving, escaped serious injury and returned to his job.

No one will be watching the proceedings more closely than Boeing and Blondin's union rivals. As Boeing prepares to build the 787 Dreamliner, its most important passenger plane in years, the company needs to repair a frayed relationship with the International Association of Machinists. Inside the union, meanwhile, Blondin's leadership has prompted sniping from critics who say he hasn't done enough to bring District 751 into the modern era.

Blondin would not comment for this story, but through a spokesperson he denied that he has held the union back. If Blondin is found guilty, he may be forced to step aside. That could open the way for new leadership at the Machinists as the two sides gear up to negotiate a new contract that must be signed in 2008.

If ever there was a time to rethink relations between Boeing and the Machinists, it's now. Beginning in 2008, Boeing will start building the 787, whose radical design requires an overhaul of the manufacturing process. At the same time, Boeing has a record number of orders. Getting them built on schedule requires it to ramp up its ambitious "lean manufacturing" program, where planes are cranked out at a faster pace as workers reduce assembly line waste and duplication. Who better than a Machinist to help advise the company on how to achieve this and, in doing so, make the job relevant for the 21st century?

Although Blondin denies it, union insiders say he has been slow to embrace lean manufacturing. It's true the cost-cutting would kill some jobs. But critics inside the union say it would also create new ones, because when the company cuts costs, it can sell more planes for more money and hire more workers. Blondin's critics say the leadership in Seattle is overly focused on restrictive work rules that, among other things, prevent Boeing from putting workers where they're most needed. "We need a long-term strategy," says one union member, who spoke on condition of anonymity. "I'm going to the lean meetings because no one else wants to go. We need to understand this."

Blondin's ascent in 2001 came amid a post-September 11 slump, when Boeing laid off 30,000 people. He has since built the district membership back up to 20,000 from 14,000--thanks in part to Boeing's resurgence. And he won a better contract than Boeing was offering--though not without a 28-day strike. "He's done a very good job," says Rick Bender, president of the Washington State Labor Council. "Mark wants to see Boeing succeed, and he wants to make sure his members get a fair shake."BAD BLOODBut union critics say members who disagree with Blondin's priorities don't get far. "Blondin is a throwback to the union's good-old-boy structure," says David Clay, a self-styled union reformer who lost to Blondin during the 2001 election. "He's more interested in perpetuating his political clique." After the last election, Clay filed a complaint with the Labor Dept., alleging Blondin's team violated labor laws to get him elected. Among the allegations: that Blondin allies threatened to revoke shop stewards' badges if they supported rival candidates. At the time, Blondin denied the allegations. The government launched an investigation, found insufficient evidence to nullify the results, and dismissed the charges. Meanwhile, in late November, the district's comptroller, Gerald Abhold, abruptly resigned. Abhold says Blondin asked him to violate budget rules, that he refused to do so, and that he was then forced out. The union says that Abhold was not ousted and denies Abhold's allegation.

Boeing declined to talk about Blondin, but insiders say the company is divided over how to deal with the union. The Chicago HQ retains some of the antagonism from the days of former CEO Harry C. Stonecipher, these people say, while the commercial plane division wants to reach out. That won't be easy. During the past two contract negotiations, in 2002 and 2005, Boeing played hardball. At the height of the negotiations in 2002, say people familiar with the matter, relations between Blondin and Boeing's then-labor relations chief, Jerry L. Calhoun, became increasingly strained. The bad blood spilled into 2005, when the two refused to talk most of the time, say the same sources. This stubbornness, they add, was as much to blame for the strike as were differences over the contract.

Relations between Boeing and the Machinists may hang on the outcome of the trial. While Boeing declined comment, it's clear the company wouldn't miss Blondin were he forced out. Then again, union insiders say there's no obvious replacement. Which adds up to more uncertainty for Boeing just as it's riding its biggest recovery in a generation. By Stanley Holmes