Suing for peace is an act by a warring nation to initiate a peace process. Suing for peace is usually initiated by the losing party in an attempt to stave off an unconditional surrender and may sometimes be favorable to the winning nation, as prosecuting a war to a complete or unconditional surrender may be costly. In this case, then, the word "sue" is being used in its original, now-obsolete meaning of "to make petition to or for", rather than the usual meaning of "to take legal action against".