Last week’s season premiere was almost breathtaking, because it was virtually breathless: John Heilemann, Mark McKinnon and new Circus correspondent Alex Wagner (replacing the disgraced Mark Halperin) covered three countries in the half-hour premiere: Russia (talking with both an official state media executive and an undercover worker at one of Russia’s fake-news rumor mills), England (getting reaction to the poisoning of two Russians on British soil), and the U.S., where President Trump chided Russia’s Vladimir Putin in a tweet for the first time, and all three countries expelled diplomats in a scary game of Cold War chess. And this week, the game both continued and reversed, making tonight’s episode, with Trump’s Russian reversal and all the James Comey coverage, a must-see.