Washington's most notorious ambassador is going home.Sergei Kislyak, 66, has been due to return to Russia since last year, after serving throughout the Obama years. But his departure became the subject of fierce speculation when it emerged that Kislyak had communicated with key members of President Trump's team before he took office.Meanwhile, in Moscow, Kislyak's replacement has been approved by two parliamentary committees and is now awaiting formal appointment by President Vladimir Putin. His name is Anatoly Antonov, a 62-year-old career diplomat known as a shrewd arms control negotiator and hard-liner on America."Antonov was smart, articulate and always well-briefed for meetings. He was a tireless advocate for the Russian position, but would also subtly probe for potential compromise," said James Miller, a former Pentagon official who met with Antonov during the Obama administration."Antonov masterfully employed the full range of human emotions, able to shift in a nanosecond from warmly charming to caustically sarcastic," Miller said.Like Kislyak and Foreign Minister Sergey Lavrov, Antonov belongs to a generation of Russian diplomats who started their careers during the Cold War.A native of Omsk, Siberia, Antonov worked his way through the ranks after graduating from the elite Moscow State Institute of International Relations with a doctorate in political science."Off camera, when you're not doing business, he is a very pleasant person to deal with," said Gary Samore, who met Antonov while working on arms control in the Obama White House. "On camera, when you're doing official business, he's a tough Russian negotiator deeply suspicious of the United States."What's unusual about Antonov is that he also served as a deputy defense minister, which led the European Union to blacklist him for his role in the war in Ukraine, which began in 2014.Antonov's expertise in arms control was the reason he was picked as Kislyak's replacement even before last November's U.S. presidential election, says Alexander Gabuev, a senior fellow at the Carnegie Moscow Center."He was meant to be war ambassador because Moscow believed that Hillary Clinton definitely would be the next U.S. president and the approach of the Clinton administration towards Russia would be very hostile and hawkish," Gabuev said.But Antonov also has a tough reputation in Moscow."He has a very hands-on managerial style. Not many colleagues like to work with him because he's a very demanding boss and a very demanding person," said Gabuev. "He is not that easy to work with."Antonov's formal appointment could be imminent, as Kislyak may return to Russia as early as this month. The controversial Russian envoy is likely to be appointed a senator in Russia's upper house of parliament, Vedomosti newspaper reported this week, citing two sources close to the Putin administration.One of the results of the Trump-Putin meeting at this month's Group of 20 summit in Germany was an agreement to speed up the process of naming new ambassadors, according to Lavrov's readout.On Tuesday, the White House announced that Trump is nominating former Utah Gov. Jon Huntsman to replace U.S. Ambassador John Tefft, who is expected to leave Moscow by the end of the summer.Huntsman has yet to face his confirmation hearing in the Senate.Antonov is already waiting in the wings. Copyright 2017 NPR. To see more, visit http://www.npr.org/.