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       WARSAW (Reuters) - Russian President Vladimir Putin could not remain in power, and his war against Ukraine has been a strategic failure for Moscow, U.S. President Joe Biden said on Saturday.

       "For God's sake, this man cannot remain in power," Biden told a crowd in Warsaw. Biden also said the Russia-Ukraine war, now in its second month, had united the West, adding that NATO was a defensive alliance which never sought Russia's demise.

       (Reporting by Jarrett Renshaw; writing by Lucia Mutikani; Editing by Nick Zieminski; Lucia Mutikani)