Trump is known to prize loyalty and the input of those who make it into his inner circle, fueling talk that the leading vice presidential contenders are New Jersey Gov. Chris Christie, Alabama Sen. Jeff Sessions and former House Speaker Newt Gingrich.

Trump is outperforming Hillary Clinton among white men, but trails in almost every other demographic. That could put retired neurosurgeon Ben Carson, Oklahoma Gov. Mary Fallin, Iowa Sen. Joni Ernst, former Arizona Gov. Jan Brewer, or Tennessee Rep. Marsha Blackburn in play.

Trump would benefit from the gravitas and policy expertise of well-respected conservatives like Tennessee Sen. Bob Corker, Indiana Gov. Mike Pence or Ohio Gov. John Kasich.

And there are wildcard picks in play, like former Massachusetts Sen. Scott Brown, or perhaps an Army general with lower name recognition.

Trump’s universe of potential candidates may be limited because some will be hesitant to join the ticket over fears that they’ll be shunned by party elites, or that the campaign is a doomed cause that will hurt their career.