What Is Robert Mueller Looking for?

Robert Mueller is the special counsel appointed by Deputy Attorney General Rod Rosenstein in May 2017 to probe the nature and extent of Russian interference in the 2016 presidential campaign. The investigation began in October 2016 under President Barack Obama when the FBI took seriously the boast of Carter Page, one of candidate Donald Trump’s foreign policy advisers, that he had worked for the Kremlin.

The FBI also had transcripts of telephone conversations and copies of emails and text mes...