<Table> <Tr> <Th> State ( linked to summaries below ) </Th> <Th colspan="3"> Incumbent </Th> <Th> Intent / Results </Th> <Th> Candidates ( listed alphabetically ) </Th> </Tr> <Tr> <Th> Senator </Th> <Th> Party </Th> <Th> Electoral history </Th> </Tr> <Tr> <Td> Arizona </Td> <Td> Flake , Jeff Jeff Flake </Td> <Td> Republican </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Deedra Abboud ( Democratic ) Jeff Flake ( Republican ) Doug Marks ( Libertarian ) Jim Moss ( Democratic ) Chris Russell ( Democratic ) Richard Sherzan ( Democratic ) Nicolas Tutora ( Republican ) Kelli Ward ( Republican ) </Td> </Tr> <Tr> <Td> California </Td> <Td> Feinstein , Dianne Dianne Feinstein </Td> <Td> Democratic </Td> <Td> 1992 ( special ) 1994 2000 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Donald R. Adams ( Independent ) Topher Brennan ( Democratic ) Jerry Leon Carroll ( Independent ) Michael Eisen ( Independent ) Dianne Feinstein ( Democratic ) Tim Gildersleeve ( Independent ) Eugene Patterson Harris ( Democratic ) David Hildebrand ( Democratic ) Charles Junior Hodge ( Independent ) Timothy Charles Kalemkarian ( Republican ) Caren Lancona ( Republican ) Richard Thomas Mead ( Independent ) John Melendez ( Democratic ) Douglas Howard Pierce ( Democratic ) Joseph Sandberg Stephen James Schrader ( Republican ) Steve Stokes ( Democratic ) </Td> </Tr> <Tr> <Td> Connecticut </Td> <Td> Murphy , Chris Chris Murphy </Td> <Td> Democratic </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Ann - Marie Adams ( Democratic ) Matthew Corey ( Republican ) Chris Murphy ( Democratic ) Dominic Rapini ( Republican ) </Td> </Tr> <Tr> <Td> Delaware </Td> <Td> Carper , Tom Tom Carper </Td> <Td> Democratic </Td> <Td> 2000 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Tom Carper ( Democratic ) Chuck Boyce ( Republican ) </Td> </Tr> <Tr> <Td> Florida </Td> <Td> Nelson , Bill Bill Nelson </Td> <Td> Democratic </Td> <Td> 2000 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Joe Allen ( Independent ) Lateresa Ann Jones ( Republican ) Edward Janowski ( Independent ) Tamika Lyles ( Democratic ) Bill Nelson ( Democratic ) Marcia Roberta Thorne ( Republican ) Joe Wendt ( Libertarian ) </Td> </Tr> <Tr> <Td> Hawaii </Td> <Td> Hirono , Mazie Mazie Hirono </Td> <Td> Democratic </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Mazie Hirono ( Democratic ) </Td> </Tr> <Tr> <Td> Indiana </Td> <Td> Donnelly , Joe Joe Donnelly </Td> <Td> Democratic </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Mike Braun ( Republican ) Joe Donnelly ( Democratic ) Terry Henderson ( Republican ) Mark Hurt ( Republican ) Luke Messer ( Republican ) Todd Rokita ( Republican ) Kiel Richard Stone ( Republican ) Andrew Takami ( Republican ) Andrew U.D. Straw ( Disability Party ) </Td> </Tr> <Tr> <Td> Maine </Td> <Td> King , Angus Angus King </Td> <Td> Independent </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Angus King ( Independent ) Eric Brakey ( Republican ) </Td> </Tr> <Tr> <Td> Maryland </Td> <Td> Cardin , Ben Ben Cardin </Td> <Td> Democratic </Td> <Td> 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Ben Cardin ( Democratic ) Sam Faddis ( Republican ) Richard `` Rikki '' Vaughn ( Democratic ) Debbie `` Rica '' Wilson ( Democratic ) </Td> </Tr> <Tr> <Td> Massachusetts </Td> <Td> Warren , Elizabeth Elizabeth Warren </Td> <Td> Democratic </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Elizabeth Warren ( Democratic ) Shiva Ayyadurai ( Republican ) Geoff Diehl ( Republican ) Mary Lindstrom ( Republican ) Darius Mitchell ( Republican ) Allen Waters ( Republican ) Heidi Wellman ( Republican ) James Devine ( Independent ) Joshua Ford ( Independent ) </Td> </Tr> <Tr> <Td> Michigan </Td> <Td> Stabenow , Debbie Debbie Stabenow </Td> <Td> Democratic </Td> <Td> 2000 2006 2012 </Td> <Td> Incumbent running </Td> <Td> John James ( Republican ) Robert P. Young Jr . ( Republican ) Craig Allen Smith ( Democratic ) Debbie Stabenow ( Democratic ) Marcia Squier ( independent ) </Td> </Tr> <Tr> <Td> Minnesota </Td> <Td> Klobuchar , Amy Amy Klobuchar </Td> <Td> Democratic </Td> <Td> 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Amy Klobuchar ( Democratic ) Jim Newberger ( Republican ) </Td> </Tr> <Tr> <Td> Mississippi </Td> <Td> Wicker , Roger Roger Wicker </Td> <Td> Republican </Td> <Td> 2007 ( appointed ) 2008 ( special ) 2012 </Td> <Td> Incumbent running </Td> <Td> Jensen Bohren ( Democratic ) Roger Wicker ( Republican ) </Td> </Tr> <Tr> <Td> Missouri </Td> <Td> McCaskill , Claire Claire McCaskill </Td> <Td> Democratic </Td> <Td> 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Angelica Earl ( Democratic ) Claire McCaskill ( Democratic ) Tony Monetti ( Republican ) Austin Petersen ( Republican )
names of republican senators up for reelection in 2018
Jeff Flake Roger Wicker Deb Fischer Dean Heller Ted Cruz Orrin Hatch John Barrasso