The MV-22 Osprey aircraft is a wonder of modern technology - able to take off like a helicopter, then fly like a plane at speeds over 300 miles per hour.
Yet, following a crash this week in the woods of North Carolina that killed four marines, the Osprey has become the latest project caught in the ongoing debate about the future of the US military.
While supporters of the Osprey say it is the ultimate weapon for the Marines, critics argue that the $38 billion program is too expensive, too dangerous, and unnecessary at a time when the United States is a lone superpower.
Full-scale production of the Osprey would certainly help the Marines' core mission of launching amphibious assaults. But "it's a weapon we don't need," says Christopher Hellman, an analyst at the Center for Defense Information in Washington.
Since its inception in 1981, the tilt-rotor craft has been surrounded by criticism. It has crashed four times, including an incident earlier this year that killed 17 marines. While accidents are not unheard of - the Marines had similar problems with the Harrier jet - the number of deaths, 30, is unusually high.
Also, the Osprey's price has steadily increased, and its technology remains a question mark. It is difficult to fly, even for the most skilled pilots.
"The MV-22 ... is not operationally suitable, primarily because of reliability, maintainability, availability, human-factor, and interoperability issues," says a November Pentagon report.
Yet the Osprey survives, and is now a living testimony to the difficulty of stopping military projects once they gather steam.
In 1989, Dick Cheney, then secretary of Defense, tried to take a whack at it, only to have Congress continue funding. In 1992, the Osprey became a campaign issue. Bill Clinton supported it. After he won the election, the program was considered a lock.
But after this year's April 8 crash in Yuma, Ariz., there was a renewed clamor to halt the program. Subsequent findings that blamed the crash on pilot error partially deflected the criticism.
Following the most recent accident, which occurred under one of the Marines' best pilots, officials said they would ground all MV-22s and stop production. Some 348 copies were planned for the Marines, 50 for the Air Force, and 48 for the Navy.
Officials say they have not determined the cause of the crash. A blue-ribbon commission will soon be assembled to assess the program's overall merits.
In the meantime, Marine Corps officials seem determined to fight for the Osprey's future. It has the tantalizing potential of allowing troops to leapfrog the shoreline in an amphibious assault, avoiding the vulnerability of a sea landing.
"I will still tell you that, having flown this aircraft ... I don't think there is anything else out there that rates with it," says Marine Lt. Gen. Fred McCorkle.
The Osprey also has friends in high places on the Hill. It is made by Boeing and Bell Helicopter Textron, with major plants in Philadelphia and Fort Worth, Texas.
One major supporter is Pennsylvania Rep. Curt Weldon (R), who said in a statement following the crash, "The V-22 Osprey remains the single best solution for the Marines' medium-lift needs."
One reason the Osprey survives is that there is no incentive to kill it, says Luke Warren of the Council for a Livable World Education Fund in Washington. "There is no way an aircraft this faulty and expensive should make it to production," he says. "There needs to be an independent, objective person, or panel, with the authority to cancel programs."
Yet, military analysts predict that it will remain difficult to stop the Osprey, even if its production is delayed for a considerable time and its longtime opponent, Dick Cheney, becomes vice president.
"It's been going on for 15 years, and an awful lot of investment has been put into it," says Paul Nisbet, an aerospace analyst at JSA Research in Newport, R.I. "The fact that it's [being built] in Texas and Pennsylvania has certainly given it more political support than it might have otherwise had."
(c) Copyright 2000. The Christian Science Publishing Society