Big weapons systems attract controversy, and the F-35 Joint Strike Fighter is no exception. Critics complain about many aspects of the program, but in the political arena all these particulars boil down to one question: Is the plane worth what the Pentagon proposes to pay for it? The case for F-35 has to be compelling, because it will cost many times more than any other weapon system the military is planning to buy through mid-century. With Secretary of Defense Leon Panetta expected to offer the administration's latest endorsement of the F-35 at Patuxent River Naval Air Station on Friday, now is a good time to recall what the bedrock rationale is for buying 2,443 stealthy, single-engine fighters.

1. Air dominance is crucial to victory in modern warfare. If you can't control the air space over contested territory, every facet of warfighting is harder. Not only are friendly ground forces vulnerable to attack from above, but the mobility, firepower, reconnaissance and resupply they count on from aircraft may not be available. That is why the first move in every recent U.S. military campaign has been to assure air dominance by destroying enemy combat planes and suppressing air defenses. Air dominance is the main reason why no U.S. soldier has been killed by hostile aircraft since the Korean War. The F-35 was designed to assure American forces will continue to have air dominance for the next 40 years, and to leverage that dominance in carrying out a range of other missions such as precision bombing and fire support of ground troops.

2. As threats evolve, air fleets must be modernized. Technology does not stand still, especially in the information age. New capabilities are continuously becoming available to potential adversaries, such as agile missiles and radars that can counter the defenses of Cold War fighters. Also, new sensors, datalinks and munitions are appearing that potentially allow U.S. planes to accomplish vital missions more effectively. However, the development of most planes in the joint fleet today predated the advent of digital information systems and stealth technology. It therefore is increasingly difficult for the joint force's industrial-age aircraft to keep up with the proliferation of new capabilities in other countries. The F-35 was designed to integrate all the technologies likely to be relevant to future warfighting, with built-in potential for upgrades as new innovations appear.

3. If America skips a generation of technology, it will lose its edge. Politicians in both parties occasionally talk about "skipping a generation of technology" as a way of avoiding the costs associated with developing current military systems. Such talk is most common when threats are thought to be receding. But that is not a practical alternative to purchasing the F-35. First, countries like India and China are already capable of defeating existing U.S. combat aircraft, and many of those aircraft have grown decrepit with age. Second, there is no way of knowing when the next big threat will appear, but being unprepared probably hastens its coming. Third, the leap-ahead option for air power usually proposed is unmanned aircraft, however they will lack the survivability, agility, versatility and lethality to match manned fighters for decades to come. Thus, if F-35 development falters America is likely to lose its edge in the air fairly quickly.

4. F-35 is the only affordable near-term solution available. The reason the F-35 program looks so expensive is that it is developing a family of planes with common features to replace the Cold War aircraft of three different military services (and a dozen allies). If each of those services was developing its own unique aircraft, the cost would be higher. And if each service decided to keep upgrading the tactical aircraft it already has for the period when F-35 is supposed to be operational, the cost would be astronomical -- about $4 trillion over 50 years, using government methodology. With production of the Air Force's F-22 fighter now canceled and no survivable fighter other than F-35 under development in the West, the Joint Strike Fighter is the only affordable option for modernizing air fleets, consuming less than five percent of the Pentagon's budget in its peak spending year. Losing a war for lack of adequate air power would incur costs far beyond the Pentagon.

Loren B. Thompson, Ph.D.