Sen. Lamar Alexander, a longtime Republican senator from Tennessee who previously served as governor, will not seek re-election in 2020.

He made the announcement on Monday that he will be retiring at the end of his current term.

“I will not be a candidate for re-election to the United States Senate in 2020. 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. I am deeply grateful, but now it is time for someone else to have that privilege,” Alexander said in a statement.

Alexander had said he would decide by the end of the year whether he’d seek re-election. As recently as last week, it seemed his team was gearing up for him to seek a fourth term, when his pollster released a poll showing the senator with a 65 percent favorability rating among likely Republican primary voters.

North Star Opinion Research surveyed 600 people from Nov. 26-29, with a margin of error of plus or minus 4 percent.