One can always depend upon Secretary of Defense Caspar Weinberger to come up with something guaranteed to protect somebody from something. So it came only as a mild surprise when I arrived at the Pentagon early on the morning of June 23 to find that, as a retired regular Army officer, I was no longer able to enter those hallowed halls.

And why was it necessary for me to forgo my appointment at the Army dispensary for an electrocardiogram, my usual visit to the Army library and a planned transaction at the Pentagon Federal Credit Union? Because Mr. Weinberger has instituted new procedures, which, according to the circular handed me, will "ensure the safety of Department of Defense employees as well as the protection of classified or sensitive information."

Among those whom the circular describes as eligible to be admitted are a) all defense people who work at least three days a week at the Pentagon; b) active-duty military personnel; and c) an assortment of others -- for example, the employees of the Federal Protective Service.

All other "visitors" must be escorted and, as though to legitimize this bit of utter nonsense, the circular reminds the reader that "the requirement for escorting is not a new procedure, but is one which has been frequently ignored in the past." If you ask me, and I've been traveling unescorted in the Pentagon since my retirement in 1966, those are hardly the right words to describe all this.

God protect us Americans from such protection. I'm waiting to read about what happens when recently retired generals Wickham and Kelley are refused admission to the Pentagon without an escort.

LEON J. FISHKIN Alexandria