Republican incumbent: Lamar Alexander
Democratic candidate: Bob Tuke
Alexander, 68, has represented Tennessee in the Senate since 2003. He is number three in his party's leadership, as chair of the Senate Republican Conference. He was governor from 1979 to 1987. At the federal level, Alexander was Secretary of Education in the Cabinet of George H.W. Bush from 1991 to 1993. He unsuccessfully sought the Republican presidential nomination in 1996 and 2000.
Tuke, 60, is a lawyer who has not served in elective office.
The polls that appear in Real Clear Politics show Alexander ahead by 24 points.
Howard Baker's 1966 victory for this seat signalled the end of Democratic hegemony in Tennessee. Then, some years after Baker's retirement, at the 1994 election, both Senate seats turned over from Democratic to Republican, and have stayed that way in the meantime.
By the way, that answers a question I raised here. When the Minnesota DFL Party lost the governorship and both U.S. Senate seats on the same day, in 1978, that scenario was not unique. All three of those offices in Tennessee were taken by Republicans on election day 1994.