Over the course of special counsel Robert Mueller’s investigation into the Trump campaign’s ties to Russia, Mike Pence has perfected a disappearing act that is almost incomprehensible in its precision.

The vice president has said he did not know about Michael Flynn’s foreign lobbying or his conversations with Russian Ambassador Sergey Kislyak. He had no comment when Flynn pleaded guilty to lying—to him, among others—about these conversations. And his office has repeatedly noted that, at crucial points in the Russia timeline, Pence was back in Indiana serving soup to the homeless or attending his son’s wedding.

Despite his efforts to shield himself from the scandal, however, Mike Pence’s knowledge—or lack thereof—has emerged as a critical piece in Mueller’s Russia puzzle.

Who sought to obstruct justice by burying the full knowledge that Mike Flynn was a traitor to the United States? Trump? Pence? Trump AND Pence?

Mueller’s Obstruction Case Could Rest on Two Simple Questions | Vanity Fair