An official with the National Labor Relations Board announced today that the Board will drop its controversial case against Boeing, The New York Times reports.

The N.L.R.B.’s acting general counsel, Lafe Solomon, said the labor board had decided to end the case after the machinists’ union — which originally asked for the case to be brought — had urged the board on Thursday to withdraw it.

On Wednesday night, the union announced that 74 percent of its 31,000 Boeing workers in Washington State had voted to ratify a four-year contract extension that includes substantial raises, unusual job security provisions and a commitment by Boeing to expand aircraft production in the Puget Sound area.

Mr. Solomon had filed the case against Boeing last April. Agreeing with the union’s position, he asserted that Boeing’s decision to build the $750 million plant in South Carolina constituted illegal retaliation against the union’s members in Washington for having engaged in their federally protected right to strike.

When I first read the NYT headline, I cheered. But the NLRB’s decision is actually somewhat of a mixed blessing. Just the threat of the case was clearly a powerful tool in the union’s negotiation of its contract renewal. Note that Boeing has agreed to expand aircraft production in the Puget Sound Area. That’s probably a sound business decision in the current climate: Better to agree to expand production in a state beset with union strife than to have to face a hostile NLRB.

But, from the very beginning, Boeing’s decision to open a new aircraft production plant in South Carolina was less a punishment of union workers in Washington than it was a reward for the leaders of South Carolina, who have conscientiously worked to make the state appealing to investors. Yes, the decision meant more new jobs for South Carolina and fewer new jobs for Washington — but it didn’t mean presently employed Washington workers would face layoffs. All of which is to say: Boeing should never have had to face this case in the first place — and the unions were still able to use the case to extort concessions from the company.

Furthermore, this could make it easier for the NLRB to follow through with its plans to institute snap elections and other disastrous policies. South Carolina Republican Sen. Lindsey Graham said he would block any Obama nominee to the NLRB as long as the Board pursued the case against Boeing. Now that the NLRB has dropped the case, Republican opposition to new nominees might not be as unwavering. An NLRB filled with Obama appointees would be even more biased toward unions than the Board we have now. Republicans in Washington need to remember this case as a warning — and still work to limit the unwarranted power of the NLRB.

Update: Rep. Darrell Issa, at least, won’t be fooled out of investigating the NLRB just because the Board dropped the case against Boeing. Check out Erika Johnsen’s excellent post for more.