Two top appointees of President Donald Trump, including the deputy secretary of State, have been embroiled in a monthslong fight that includes accusations of leaks to the media and “bizarre” threats of defamation — all over emails that at times included more than a dozen administration officials. The conflict centers on Paolo Zampolli, a personal friend of Trump’s and a special envoy at the State Department, and Deputy Secretary of State Christopher Landau, according to the messages obtained by POLITICO. The emails stretch over almost a year and show Zampolli and Landau disagreeing over chains of command as Landau admonishes...