The insertion of Russian prepositions in negative and reciprocal pronouns as well as in indefinite pronouns with koye- and the insertion of weak dative pronouns in the syntactic idiom tak 〈Х-u〉 i nado ‘X deserved it’ are regular instances of endoclisis. Russian also displays the clitic/weak form vs stressed form asymmetry with some other syntactic idioms. Russian endoclitics may lack complete features of phonetic clitics. In Russian negative pronouns and indefinite pronouns with koye-, the linear order with endoclitic insertion embodies the logic-semantic hierarchy of two operator elements in the context of embedded PP-arguments. In Russian reciprocals and in the idiom tak 〈Х-u〉 i nado endoclitic insertion lacks a clear semantic motivation.