and from leon sigal who has written extensively about u.s.- korean relations. he's with the socl science research council, an independent think tank in new york. ambassador hill, does the joint u.s./south korean naval exercise make sense to you? >> yes, it does. because i think the key element of any u.s. policy for north korea has to be the relationship with south korea. you know, this relationship is getting better and better. south korea's emerged as not only a major partner for us regionally but even globally as we've mean? the g-20 meeting. so i think it's very important that we stay in tight formation with the south koreans. and i think an exercise of this kind is entirely appropriate. >> lehrer: leon sigal, do you agree? it sends a message and it's the right message? >> i think the first thing you do is you reassure your ally. but we also have to think about how we play our way through this so we can find a way out. and that's also important for bringing the south koreans along. we need to find a path to get us out of the pernicious interaction between t