Trump is considering picking Gingrich for a top national security post should he be elected president, according to two people familiar with the the candidate’s thinking.

A longtime backer of Trump’s campaign, Gingrich was added to the short list of vice presidential candidates in May. While Trump could still ask Gingrich to join the ticket, his focus has narrowed in recent days to Indiana Governor Mike Pence and New Jersey Governor Chris Christie, the Washington Post reported on Monday.

A national-security role in a potential Trump administration could be a good fit for Gingrich. He holds a doctorate in European history and is known for his intellectual curiosity. In Congress, he immersed himself in military affairs and intelligence issues, and in 2001 he was named by then-President George W. Bush to serve as a member of the Pentagon’s Defense Policy Board. Like Trump, Gingrich is a staunch critic of the the U.S. nuclear deal with Iran.

Asked about the potential role, Gingrich said, “I know nothing of this.”