In expressing his reservations about the proposed U.S.-U.S.S.R. arms accord, Rep. Jack Kemp informed reporters that he objected "to the idea that you can just reduce one theater level of weapons without talking about the Warsaw Pact's preponderance of tanks and, of course, the first-strike capability that is still a threat to Europe" {news story, Sept. 20}.

Although Rep. Kemp's concern over Warsaw Pact conventional capability vis-a`-vis that of NATO is warranted, his reference to first-strike capability is erroneous. Neither Warsaw Pact nations nor NATO nations possess a genuine first-strike capability; instead each group has the capability to employ the first use of nuclear weapons.

First-strike capability is the ability to knock out the opponent's nuclear arsenals (which include land-, sea- and air-based missile systems) in an all-out strategic attack. First use refers to the limited use of nuclear weapons in a limited area of combat in response to an unstoppable conventional war. These two concepts and their implications are central to both U.S. and Soviet nuclear doctrine.

It seems to me that if Rep. Kemp wishes to air his views on arms control issues, he should first master the fundamentals, and then express his opinions to the American people. KATHY SCHNEIDER-KOENIGS Manassas