MONTGOMERY, Ala. — Sen. Richard Shelby, the Senate’s fourth most senior member and a force in Alabama politics for more than four decades, announced Monday that he will not seek a seventh term in office in 2022.

The 86-year-old Republican has spent more than 40 years in Washington, serving first in the House and then the Senate.

During his time in the chamber, he chaired four major Senate committees, using his position and deal-making skills to direct billions in projects back to his home state.

Shelby is the fourth Senate Republican to announce his retirement, following Sens. Rob Portman of Ohio, Pat Toomey of Pennsylvania and Richard Burr of North Carolina.

His departure will leave a power void — and set the stage for a chaotic race to fill the seat at a time when the national Republican Party is deeply split on its future direction after former President Donald Trump’s term in office. While Shelby has amassed a far right conservative voting record, the measured Republican senator has not embraced the bombastic populist style of some Republicans.

In 2017, Shelby bucked his party when he announced that he could not support Republican Roy Moore, who faced sexual misconduct allegations, in the special election for Alabama’s other Senate seat. And last month, he was the only Republican in Alabama’s congressional delegation who voted to accept the presidential election results certified by Arizona and Pennsylvania. The other Republicans objected to the certifications in support of Trump’s baseless claim that the election was stolen.

Shelby’s official announcement that he would not run for reelection in 2022 came three days after The Associated Press reported that he had indicated to allies that he wouldn’t run again.

“For everything, there is a season,” Shelby said. “I am grateful to the people of Alabama who have put their trust in me for more than 40 years.”

The senator stressed that he will finish the two years remaining in his current term and remarked, “I have the vision and the energy to give it my all.”