(FORTUNE Magazine) – Two years ago, your correspondent had a part-time tour of duty in the Pentagon, serving as editor for a high-level group called the Commission on Integrated Long-Term Strategy (CILS). The commission was co-chaired by Fred C. Ikle, deputy secretary of defense for policy, and Albert Wohlstetter, and included such additional heavyweights as Henry A. Kissinger and Zbigniew Brzezinski. The experience proved highly educational for the editor, as it also would have for the U.S. Congress if there were only some way to tie those guys down and make them pay attention. Among the thoughts we came away from CILS with was the transcendent strategic importance of ''low-observable'' (a.k.a. Stealth) technology, especially the Stealth bomber now being kicked around by Congress and numerous members of the media. Gasping over its cost and concluding that the plane is generally a bad idea have been influential Republican Congressmen, gaggles of op-edsters, Washington Post and New York Times editorials, and a major article in -- whoops -- FORTUNE (''How Big a Military Does the U.S. Need?'' July 31). Also suddenly onstage is the idea that any bomber would now be out of date. As California Congressman Ron Dellums put it in a Washington Post diatribe, the Stealth B-2 ''is as irrelevant in the nuclear missile age as the Polish cavalry was against German tanks in September of 1939.'' Dellums added the familiar thought that we now have a ''changed international climate,'' so why are we still loading up on expensive hardware? To take the last argument first, this is precisely the right time to be moving forward on high-tech weapons systems. Always on the minds of defense planners is the inescapable trade-off between spending to deal with long-term and short-term threats. If you are in a defense environment where the threats look real and imminent, you obviously spend heavily on readiness -- on manpower, training, ammunition -- and defer investments in the big weapons systems of the future, which can take a decade or more to get into the inventory. When today's environment looks tolerably unthreatening, you reverse course. You now look for economies in readiness, and invest in technologies that will keep you at the leading edge in the unknowable security environment of 1999. We asked Fred Ikle the other day about the Polish cavalry argument, and he said he could make a case that in the nuclear age it is increasingly ICBMs, not aircraft, that look ineffective. These missiles can deal only with the ''extreme contingencies'' -- a Soviet invasion of Western Europe, an all- out nuclear strike against the U.S. -- which do indeed need deterring but which (the CILS report argued) are far less likely than many other important contingencies. The extreme contingencies have been overemphasized in U.S. defense planning. Underemphasized have been capabilities for nonapocalyptic, discriminating responses, including many that would use nonnuclear weaponry. The B-2 has the versatility to make such strikes. Essentially undetectable by radar, it can penetrate Soviet airspace, search for targets, hit them with nuclear or conventional weapons, verify that the targets were hit, and return home safely; furthermore, it can do all these things from North America. A major offset against the aircraft's cost is its ability to function without expensive overseas bases. The B-2 is also the prime example -- possibly the only legitimate example -- of something the Pentagon calls ''competitive strategies.'' The thought behind that phrase is that we get an outsize strategic payoff when we field weaponry that undermines systems in which the other side has invested heavily. The Soviets have made colossal investments, which Stealth would instantly devalue, in networks of radar-based air defense. It could be the biggest write-down in history.