THE ADMINISTRATION is asking Congress to do an extraordinary thing. With the barest of public debate, without even public disclosure of the cost, it is asking the members to approve what is widely expected to be one of the most expensive weapons programs ever undertaken. The barely visible object of expenditure is Stealth, the bomber of the future that the Air Force hopes can also be made largely invisible to Soviet radar. For various reasons, some worthier than others, members of Congress have begun questioning the project. The Pentagon's response has been mainly to regret that it cannot respond publicly (there have been briefings for those with clearances), because Stealth is secret. Clearly there are times and good reasons for secrecy in defense. Here the department has gone too far.

The bomber debate has been going on for 15 years. The question is what should replace the B-52s that now make up the nuclear bomber fleet. These are old and no longer thought capable of penetrating Soviet defenses. The original Air Force candidate to succeed them was the B-1. Amid great controversy President Carter prevailed upon Congress to cancel the B-1 in 1977. It turned out later he had done so in favor of Stealth, even though Stealth will take at least until the early 1990s to produce. The argument was that the country could afford the risk of waiting for what looked to be the better bomber.

President Reagan reversed the Carter decision in 1981 and proposed building both bombers. Congress at his behest agreed to buy 100 B-1s in advance of Stealth as a kind of insurance policy. For a while it seemed that the long debate was finally over. But now Rockwell International is approaching the end of its contract to build the 100 B-1s; the last is scheduled to come off the line in 1988. To keep the line open, the company has shrewdly offered to build another 48 at greatly reduced cost. There are said to be 20,000 jobs at stake and subcontractors in 48 of the 50 states. The issue with B-1, which used to be whether to build it, has now become whether to stop.

Jobs are insufficient reason to build any weapon, but this is not the only level at which there is debate. The Rockwell offer and the tightening budget have combined to reopen the question of Stealth's cost-effectiveness as well. More money for one bomber would presumably mean less and a delay for the other. The Pentagon, partly to protect Stealth, says 100 B-1s are all it wants. The questions about Stealth concern its cost and the effectiveness of its technology. A more radical school has also raised the question of whether there still is a need for a penetrating bomber. These people suggest a cheaper though in some ways lesser alternative: a bomber that can stand off and fire cruise missiles. B-52s are being equipped to do this now, and B-1s could be later.

Some of the best minds in the Pentagon say the case in favor of Stealth is overwhelming. They should make it publicly. People who know say they can disclose much more than they have without disclosing the technology, which is the key. Congressional analysts say that the black part of the Pentagon budget is increasing, meaning more is being kept from public view. But weapons decisions are about trade-offs; they cannot be made this way. Blacked-out requests are a dangerous way to go.