Tennessee [3] Republican Rep. David Davis [4] became the fourth member of the U.S. House of Representatives to be booted by primary voters this election cycle, when he was defeated by Johnson City Mayor Phil Roe [5] on Thursday. Across the state, Rep. Steve Cohen [6] (D) easily defeated his main rival, Nikki Tinker [7], who had used racially charged images in campaign ads attacking Cohen.

Davis was elected in 2006 after besting 12 other Republican candidates in the primary. Roe was among those who lost 2 years ago, but with a smaller field he was able to mount a successful challenge to the freshman representative. Roe is favored to win the November election, since the 1st congressional district leans Republican.

Davis is the latest incumbent [8] to fall to partisan challengers this year: Reps. Chris Cannon [9] (R-Utah), Wayne Gilchrist [10] (R-Md.) and Albert Wynn [11] (D-Md.) were also voted out in primaries.

Meanwhile, Cohen (another freshman representative) won his primary battle by a landslide 60-point margin. Democrats in his majority-black 9th district gave him 79 percent of the vote, while Tinker pulled in 19 percent. Tinker had used an image of Ku Klux Clan founder Nathan Bedford Forest in an ad attacking Cohen, who is white and Jewish. Cohen should have an easy victory come November in the heavily-Democratic district.

Also Thursday, Democrats nominated law professor Bob Tuke [12] to take on Sen. Lamar Alexander [13], the Republican conference chair in the Senate.

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Here are the victors of Tennessee [3]’s primaries:

• Sen. Lamar Alexander [13], the Republican conference chair in the Senate, is being challenged by Bob Tuke [12], a partner in a law firm and professor at Vanderbilt’s law school.
• In the 1st district, Republican incumbent Rep. David Davis [4] lost a primary election to Phil Roe [5]. Roe will face Democrat Rob Russell [16], an administrator at East Tennessee State University.
• In the 2nd district, incumbent Rep. Jimmy Duncan [17] (R) is running against Bob Scott [18] (D), a retired professor at Pellissippi State Technical Community College.
• In the 3rd district, incumbent Rep. Zach Wamp [19], a Republican, is facing Doug Vandgriff [20], a Wal-Mart employee.
• In the 4th district, incumbent Rep. Lincoln Davis [21], a Democrat, is up against Republican Monty Lankford [22], who owns TLC Medical Oxygen & Hospital Equipment, Inc.
• In the 5th district, incumbent Rep. Jim Cooper [23] (D) is being challenged by Gerard Donovan [24] (R), who founded a training and consulting firm.
• In the 6th district, incumbent Rep. Bart Gordon [25] (D) has no major party opposition.
• In the 7th district, Republican incumbent Rep. Marsha Blackburn [26] .
• In the 8th district, Democratic incumbent Rep. John Tanner [27] is uncontested in November.
• In the 9th district, incumbent Rep. Steve Cohen [6] (D) also has no major-party competition.