The 2 Democratic gains came from the defeats of incumbents Kelly Ayotte in New Hampshire and Mark Kirk in Illinois by Maggie Hassan and Tammy Duckworth, respectively.

[69] Other potential Republican primary challengers included 2010 nominee and 2014 candidate Joe Miller, State Senator Mike J. Dunleavy, former lieutenant governor Mead Treadwell, and former mayor of Anchorage Dan Sullivan.

[70] The only person to file for the Democratic primary as of May 20 was writer and satirist Richard Grayson, who previously sought election to Wyoming's House seat in 2014.

[18] McCain faced primary challenges from Fair Tax activist Alex Meluskey,[citation needed] businessman David Pizer,[81] talk radio host Clair Van Steenwyk,[82] and State Senator Kelli Ward.

Other Democrats on the primary ballot included "President" Cristina Grappo, Massie Munroe, Herbert Peters, Emory Rogers, and Steve Stokes.

Former state Republican Party chairs Tom Del Beccaro[109] and Duf Sundheim,[110] and former state senator Phil Wyman[111][112] ran, along with Don Krampe,[113] Tom Palzer,[114] Karen Roseberry,[115] Greg Conlon, Von Huogo, Jerry Laws, Ron Unz, Jarrell Williamson, and George Yang.

[23] State Representative Dan Carter,[24] apparel company CEO and 2004 Senate nominee Jack Orchulli,[135] and former Olympic athlete August Wolf[136] ran for the Republican nomination.

In April 2014, Rubio stated that he would not run for both the Senate and President in 2016, as Florida law prohibits a candidate from appearing twice on a ballot.

[25] U.S. Representative Ron DeSantis, combat veteran Todd Wilcox,[146] real estate developer Carlos Beruff,[147] retired college lecturer Ilya Katz,[148] and Donald J. DeRenzo ran for the Republican nomination.

[27] In 2015, Isakson announced he was being treated for Parkinson's disease, but stated that his treatment would not interfere with his re-election campaign or his ability to serve another term.

[159] Investment firm executive Jim Barksdale,[28] project manager Cheryl Copeland,[160] and businessman John Coyne[161] ran for the Democratic nomination.

"[182] Joe Walsh, a former U.S. Representative and conservative talk radio host, declined to challenge Kirk in the Republican primary.

[187] U.S. Representative Tammy Duckworth,[188] President and CEO of the Chicago Urban League, Andrea Zopp,[189] and State Senator Napoleon Harris ran for the Democratic nomination.

[224] Lexington Mayor Jim Gray,[36] Rory Houlihan,[225] Ron Leach,[226] Sellus Wilder[227] Jeff Kender, Tom Recktenwald (who was a candidate in 2014), and Grant Short ran for the Democratic nomination.

[240] Other potential Democratic candidates included state legislators Robert Johnson, Eric LaFleur, and Gary Smith Jr., and Mayor of Alexandria Jacques Roy.

Representatives Donna Edwards[248] and Chris Van Hollen,[39] Freddie Donald Dickson Jr., Ralph Jaffe, Theresa Scaldaferri, Charles Smith, Violate Staley, Blaine Taylor, Ed Tinus, and Lih Young.

The Republican candidates who filed were former Deputy Assistant Secretary of Defense and Senate candidate in 2012 Richard Douglas,[250] Chrys Kefalas,[251] State Delegate Kathy Szeliga,[40] Chris Chaffee, Sean Connor, John Graziani, Greg Holmes, Joseph David Hooe, Mark McNicholas, Lynn Richardson, Anthony Seda, Richard Shawver, Dave Walle, and Garry T.

For the Democrats, Secretary of State Jason Kander[42] easily won the nomination, defeating Robert Mack, Pastor Cori Bush,[257][258] and activist Chief Wana Dubie.

[264] Former Nevada Attorney General Catherine Cortez Masto earned the Democratic nomination, defeating Bobby Mahendra, Liddo Susan O'Briant, and Allen Rheinhart in the primary on June 14, 2016.

Congressman Joe Heck[43] defeated eight candidates, including 2010 nominee Sharron Angle,[265] who ran against Reid in 2010, for the Republican nomination.

[274] U.S. Representative Richard L. Hanna, Manhattan Republican Party Chairwoman Adele Malpass, and former CNBC television host Larry Kudlow[275] were also mentioned as possible candidates, but all declined to run.

[47][281] Three Republicans challenged Burr in the primary: Greg Brannon,[282] Larry Holmquist,[283] and former Superior Court Judge Paul Wright.

[285] Former state representative Deborah Ross,[48] Spring Lake Mayor Chris Rey,[286] businessman Kevin Griffin,[287] and retired U.S. Army Captain Ernest Reeves[288] ran for the Democratic nomination.

He ran unopposed in the March 15, 2016 primary, and received enough votes to substantially increase the number of enrolled Green Party members.

[23] Medford City Councilor Kevin Stine[308] and retired locomotive engineer Paul Weaver[309] challenged Wyden for the Democratic nomination.

He resigned at the start of 2013 to become president of The Heritage Foundation, and U.S. Representative Tim Scott (Republican) of South Carolina's 1st congressional district was appointed to replace DeMint by Governor Nikki Haley.

[56] Other potential Democratic candidates included State Senator Bernie Hunhoff[329] and filmmaker and former television news producer Sam Hurst.

[330] Former U.S. Representative Stephanie Herseth Sandlin, Sioux Falls Mayor Mike Heuther, and 2014 nominee Rick Weiland all declined to run.

[339] Marriage therapist Jonathan Swinton[340] and grocery store clerk Misty Snow, a transgender woman, ran for the Democratic nomination.

[58] Scott Milne, the Republican nominee who narrowly lost the 2014 Vermont gubernatorial election, ran unsuccessfully against Leahy.