When Iran last month finally accepted a United Nations resolution calling for a cease-fire in the eight-year war with Iraq, it seemed that an end to the fighting was near at hand. But as both parties are finding out, it's much easier to start a war than to stop one.

For years, Iran had been the intransigent one, refusing to even consider negotiations to end the war unless the government of Iraq was overthrown and Iraqi strongman Saddam Hussein deposed. Iraq had said it was ready to talk peace, but could not accept such a precondition.Now that Iran has accepted the U.N. cease-fire resolution without preconditions, Iraq is making trouble. Iraq is insisting on Iran's agreeing to face-to-face talks as a precondition for a truce, saying Iran cannot be trusted otherwise.

Why the switch in positions? Mostly it has to do with success on the battlefield. Iraq had been losing until recently, when a series of crushing victories threw Iran back behind its own border.

Flushed with success, Iraq now seems bent on making Iran accept certain terms for a cease-fire - something the Iranians refuse to do. In fact, Iran is threatening to raise some conditions of its own.

All of this is disappointing, but there is no reason to give up hope. Cease-fire deals typically are hard to arrange and often break down before a final truce is reached. This war is no different.

There is hope for a cease-fire because both countries are war weary, neither can totally defeat the other, and each is substantially back behind its own border - the same lines where the whole thing began.

While an eventual cease-fire can be expected, there is one legacy of this war that is deeply troubling. Iraq openly used poison gas against Iranian targets and, in fact, is continuing to do so.

That is bad enough, yet what is worse is the rest of the world letting them get away with it. Poison gas has been outlawed since 1925. Nations have used it from time to time since then, but have always tried to deny the use. Iraq has not only used chemical weapons, but has admitted it - without any consequences.

What a terrible precedent and example to other nations in the Third World. Those nations may not be able to afford missiles, but they can cheaply resort to using poison gas. A horrifying door has been opened that may not be easily closed.