Absent Soviet agreement to such a ban (like the one that ultimately emerged in the INFTreaty with respect to medium-range ballistic missiles), any reductions agreed to in START could be readily circumvented without detection.
Recently, the U.S. government discovered in East Germany a number of undeclared, operational launchers (reportedly 6) for the INF Treaty-limited SS-23 shorter-range missile system, together with a significant quantity of associated missiles (reportedly as many as 24).
After the Bush Administration's compliance report was sent to Capitol Hill, the U.S. government discovered in East Germany a number of launchers (reportedly 6) for the INF Treaty-limited SS-23 shorter-range missile system, together with a significant quantity (reportedly as many as 24) associated missiles.
Furthermore, even if the Soviets had transferred the SS-23s to East Germany before the INFTreaty was signed -- a contention unsupported by any public evidence at this time -- the existence, declaration, and elimination of all such weapons would have been directly relevant to the negotiation of that accord.
GLCM's were eventually scrapped as part of the terms of the Intermediate Nuclear Forces (INF) Treaty signed between the United States and the former Soviet Union.