It is legitimate, in principle, for a journalist to interview a murderous dictator. The uproar over Tucker Carlson’s announcement that he would interview Vladimir Putin was that the session would amount to pure Kremlin propaganda. Carlson, after all, is an admirer of Putin who, in his days as a Fox News host, hoped out loud that Russia would win its war against Ukraine. It was also feared that Putin would spout a stream of lies and that Carlson, who is not a real journalist, much less a historian, would be incapable of pushing back. In this sense, the two-hour interview,...