Tuesday afternoon, in a room on Capitol Hill, a group of House members will vote on the fate of a jet engine, adding yet another battle to a years-long lobbying war between two big defense contractors.
The stakes are enormous, because the F-35 -- known as the joint strike fighter -- will be the only new U.S. fighter jet for years to come. So the competition for engines has gotten vicious.
The Pentagon decided four years ago that Pratt & Whitney would get this engine contract. President George W. Bush backed that decision, and so does President Obama.
But every year, Congress votes money for General Electric to continue developing a competing engine.
These companies -- Pratt & Whitney and GE -- are pillars of the American military industrial establishment. Pratt powered armadas of American planes in World War II. And GE thrust the first American jet fighter into the air in 1942.
But they're not acting like pillars right now. They're acting more like political candidates.
"You're going to have a $100 billion monopoly from one engine manufacturer who's already grossly over budget," says GE Aviation spokesman Rick Kennedy. He says Pratt is angling for a fat government handout.
And just this month, GE put up a video of former Navy Secretary John Lehman that looked like an attack ad against Pratt & Whitney.
"The F-14, 30 percent of the accidents came from this lousy engine," Lehman says in the video.
That would be a Pratt & Whitney engine.
"It wasn't until the GE competitive engine came in and was put into the F-14D that the accidents from engine failure ceased. Stopped. Many lives saved," Lehman contends in the video.
In its rebuttal, Pratt & Whitney points out that Lehman was talking about something that happened 25 years ago, on a different project.
David Manke, a lobbyist for Pratt's parent company United Technologies, says the new engine for the F-35 had some problems along the way. But now it's certified for production in the first run of joint strike fighters.
GE's engine is not certified.
"The other guys, they're probably four or five years behind us," Manke says. "You know, with a paper engine, that's going to be perfect. When you have a real engine, there can be flaws -- so we thought we had to come out and protect ourselves."
And Pratt has its own attack video against GE. It starts with footage of Obama promising to cut Pentagon programs that don't keep America safe.
"One example," the president says, "is a $465 million program to build an alternate engine for the joint strike fighter."
GE says engine competition will actually save money.
The rhetoric you hear from the lobbyists is echoed by members of Congress who have a dog in the fight.
Rep. Steve Driehaus, a Democrat from Cincinnati, the home of General Electric, had this to say about Pratt in a House debate: "They want to be declared the winner of the race while all the contestants are still at the starting line."
Rep. Rosa DeLauro, a Democrat from Connecticut, home of Pratt & Whitney, went after GE's alternate engine:
"The Marines don't want it. Air Force doesn't want it. Navy doesn't want it. Why are we moving ahead with it?"
Why is this debate so red hot?
Winslow Wheeler of the nonprofit Center for Defense Information says he used to see infighting like this all the time when he worked on Capitol Hill. But in years past, everyone would keep quiet about it.
"But once it gets to be a public debate in Congress, those bars are removed," Wheeler says. "And the catfighting gets to be very public."
And then there's this: When the joint strike fighter is in full production, it will be the only U.S. fighter plane in production -- and, for engine makers, the only game in town.