Scott, a wealthy health care executive who had never held public office before, won the job with less than a majority in 2010, and his first term has been marked by low approval ratings and struggles against the GOP-led legislature. [...] unpopular among conservatives in part for backing Obama's economic stimulus law, he ran as an independent rather than face GOP primary voters. Crist finished well behind the eventual winner, Republican Marco Rubio, but still relegated the Democratic nominee to an even more distant third. [...] Crist declared he was a Democrat, complete with a full embrace of the Obama administration. [...] state Treasurer Doug Ducey has painted himself as the front-runner in the race, citing a broad coalition of business leaders and other political figures. Dan Feliciano is a Libertarian, but he's running for the Senate as a write-in candidate in the Republican primary against three other candidates — Scott Milne, Steve Berry and Emily Peyton — whose names appear on the ballots.