The office of former President Barack Obama in March privately bashed Senate Republicans’ investigation of former Vice President Joe Biden and his son in Ukraine, a probe it deemed as lending credence to a “Russian disinformation campaign,” according to a letter obtained by Fox News. The letter, addressed to the National Archives and Records Administration (NARA), which manages presidential records, was written in response to a request on Nov. 21, 2019, by Republican Sens. Chuck Grassley and Ron Johnson for Obama administration records on Ukraine-related meetings. The letter referred to their request as improper use of the NARA’s release terms...