The facility the United States bombed in Baghdad Tuesday night does not look, even on Iraqi-censored television, like an innocent hiding place.

Obvious in the television films of what the Iraqis say is a purely civilian bomb shelter is the 8-foot tall chain-link fence, topped with barbed wire. Clear in the inside shots are cable runs overhead in the corridors. To anyone who has ever been in a hardened command post or communications center, those cable trays are a dead giveaway of the use of the facility.This was a tough, reinforced military command post, make no mistake about it. Possibly Iraq could have turned it over to civilians, but the United States should not be faulted for targeting it.

The intelligence the United States has about its targets is truly amazing. Obviously, our satellites can look into every back yard in Baghdad and count the stars on the shoulders of the Iraqi generals. Anyone who has been familiar with the U.S. National Security Agency has known for years that we can monitor and decipher radio communications. What is less well-known is our capability to detect and read even communications over land-line communications such as teletype and telephone.

The description by Lt. Gen. Thomas Kelly of the Iraqi facility as protected against electromagnetic pulse from a nuclear explosion was probably a euphemism for what is known as "Tempest" shielding in the U.S. military.

One of the best-kept secrets of "sigint" or electronic signals intelligence is the fact that even hard-wired communications give off detectable signals that the United States can pick up from satellites. By aiming extremely sensitive small dish antennas from satellites at suspected communications sites we can read what Saddam Hussein is telling his troops. The basic principle is obvious to anyone who has noted a click in his radio when a nearby light switch was turned on or off.

When the contacts of a teletype or computer keyboard or the computer pulses of a coding machine, even in a "secure" telephone, are transmitted in typical binary code, the pulses create tiny bits of electrical hash or noise.

This was discovered by the United States in the 1960s when a NSA monitor parked a van outside a supposedly secure Navy facility near Philadelphia and produced uncoded records of coded transmissions, based purely on the electrical "hash" the secret TOTEM encryption systems were putting out. The code machines' electrical contacts were transmitting the plain texts of the secret messages before they were encoded.

Very quickly, the United States put into place a program of hardening such signals, under the code name TEMPEST.

Our officials aren't saying, but it appears obvious that we can read a great deal of the Iraqis' signal traffic; certainly we can tell where it is coming from. Also obvious from the reports out of Baghdad is the fact that Saddam offset any radio antennas from this facility, locating them miles away from the transmitters themselves, as they would be an obvious giveaway on which to home attacking missiles. No surprise there.

Was this facility possibly used as a shelter for the Iraqi military leaders and their families, a place where they mistakenly though the allied air forces could not find them, where they would be safe under many feet of reinforced concrete?

Well, tragic as it may have been, U.S. planes put two bombs directly down the air shafts of this command center, destroying a military center and perhaps helping prevent a ground war that Iraq hopes will kill many coalition men and women.