What if the propose war option had a date that was proposed and when accepted, war would begin right on the tick of that date? For example, Kingdom A proposes war begins on June 1st, YR0 with Kingdom B. Kingdom B must accept prior to May 24th, YR0 and war begins on June 1st, YR0. The proposal would expire on May 24th, YR0 if Kingdom B does not accept. That gives at the least a full hour of warning to both kingdoms that war will begin.