Trump resists Mueller interview, leaving difficult decision on subpoena before fall elections

That’s nonsense. It’s actually nonsense on stilts,” said Paul Rosenzweig, who worked with the independent counsel’s office that investigated President Clinton in the 1990s and is now a senior fellow at the R Street Institute, a nonpartisan think tank in Washington.

The only grounds required for obtaining a grand jury subpoena, Rosenzweig said, is whether a witness may have evidence germane to the investigation.