Ukraine’s UN ambassador Yuriy Sergeyev argues that Russian President Vladimir Putin is threatening the world as part of a “maniac idea” to assert Russia as a world power again — “What he is doing makes us treat him like he has a serious disease.” Ukraine’s UN ambassador Yuriy Sergeyev argues that Russian President Vladimir Putin is threatening the world as part of a “maniac idea” to assert Russia as a world power again — “What he is doing makes us treat him like he has a serious disease.”