Who's running and who could run in 2016?

POSTED: 10:41 AM Nov 08 2012   UPDATED: 10:34 AM May 27 2015

Rick Santorum announced his candidacy for the 2016 presidential election on Wednesday. Check out other formally announced or potential 2016 candidates.

Rick Santorum
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Rick Santorum, the former Pennsylvania senator who mounted an unexpectedly strong bid for the Republican nomination in 2012, is making another bid for the White House. Santorum is formally launching his campaign May 27 in Pennsylvania, spokesman Matt Beynon confirmed to CNN.