Republican Sen. Lamar Alexander of Tennessee said he won't run for re-election in 2020, adding to the GOP's challenges in keeping control of the chamber in two years.
Alexander, a former two-term governor of Tennessee and the current chairman of the Senate Health, Education, Labor and Pensions Committee, said in a statement Monday that after three Senate terms it's time for someone new to represent the state.
"The people of Tennessee have been very generous, electing me to serve more combined years as governor and senator than anyone else from our state," he said. "I am deeply grateful, but now it is time for someone else to have that privilege."
The departure of Alexander, 78, will open a vacancy atop a Senate panel that covers public schools, colleges, labor rights and the U.S. health care system. Tennessee is a Republican-leaning state, so whoever the GOP nominates would likely start as a favorite to retain Alexander's seat.
Yet Republicans face challenges in keeping control of the Senate after 2020, so the departure of a popular incumbent is a step back. Republicans picked up two seats in the November elections to gain a 53-47 seat majority when the next session of Congress starts in January. In two years, they'll have to defend 22 seats, compared with just 12 for Democrats.
Competitive Seats
Republican-held seats in Arizona, Colorado and Maine are considered competitive. Republicans have only one likely 2020 pickup opportunity, in Alabama where Democratic Senator Doug Jones will be seeking re-election in a heavily Republican state.
There are no clear front-runner Tennessee Senate candidates in either party for 2020, said Jennifer Duffy, Senate editor of the nonpartisan Cook Political Report. She said Democrats might look to 2018 gubernatorial nominee Karl Dean, the former mayor of Nashville. State House Minority Leader Craig Fitzhugh is another possibility, she said.