Sen. Jay Rockefeller, a West Virginia Democrat and chairman of the Senate Commerce Committee, plans to retire at the end of his term.

Rockefeller, 75, a  senator since 1985, would have faced a difficult re-election next year. Rep. Shelley Moore Capito, R-W.Va., a popular congresswoman, plans to seek the seat, and Rockefeller has been a supporter of President Barack Obama in a state where the president has not been popular.

He's also fought with the state's coal mining industry in recent years. He'll probably be most remembered for his work on overhauling the nation's health care system.

“As I approach 50 years of public service in West Virginia, I’ve decided that 2014 will be the right moment for me to find new ways to fight for the causes I believe in and to spend more time with my incredible family. Serving West Virginia in the U.S. Senate is an abiding honor and privilege, and Sharon and I are so full of gratitude to our state and to the countless friends and supporters who have made my public service possible,” Rockefeller said. “For the next two years in the Senate, and well beyond, I will continue working tirelessly on behalf of all West Virginians. Championing those most in need has been my life’s calling, and I will never stop fighting to make a difference for the people who mean so much to me.”