It’s not clear whether the freshman Republican senator and tea party star has received paperwork from the campaign or is just being scrutinized through the wealth of publicly accessible information about her.

New Jersey Gov. Chris Christie, former House Speaker Newt Gingrich and Indiana Gov. Mike Pence are also being vetted, the source said. A senior Trump campaign adviser confirmed Pence is being formally vetted.

A senior Trump adviser confirmed that Ernst is being considered, but that it’s not clear that Ernst is interested “as opposed to others who have said, ‘Thanks, let’s play ball.'”

Ernst’s office has not responded to requests for comment.