Sen. Karen Peterson, 66, announced Tuesday she will not seek re-election. She has pushed for death penalty repeal, a higher minimum wage and criminal justice reform. (Delaware State News/Marc Clery)

DOVER — Sen. Karen Peterson, a Stanton Democrat who has been an outspoken liberal during her 14 years in the Senate, said Tuesday she is not seeking re-election.

She made the announcement at the start of the legislative day, much to the shock of colleagues who were unaware of her plans.

A champion of many liberal causes, Sen. Peterson, 66, has pushed for death penalty repeal, a higher minimum wage and criminal justice reform.

“Karen doesn’t just stand up for what was right, she fights for it,” President Pro Tempore Patricia Blevins, D-Elsmere, said in a statement. “She is among the most articulate, passionate and well-prepared lawmakers that Dover has ever seen and as a result she has moved the needle on so many issues: expanding civil rights, increasing government transparency and protecting children and families.”

Gov. Jack Markell, a Democrat, praised Sen. Peterson in a statement, calling her “an important voice and public servant.”

No one has yet filed to run for the 9th District Senate seat. Democrats outnumber Republicans 2-1 in the district.

Sen. Peterson noted that no Republicans have filed in a brief speech on the floor Tuesday, but said she knew it was time to leave.

“The older you get the more you realize that life is short, and there are lots of other things I want to do in life while I’m still able to do them,” she said.

She received a standing ovation after her announcement.

Sen. Peterson said afterward she had been considering retiring for some time. She finally decided recently to “kick back a little and relax.”

“I have a lot of hobbies. I have piles of books to be read that just collect dust because everything I read starts with ‘whereas,’” she joked.

She told her family only hours before she made the official announcement.

While parts of five representative districts reach into the 9th Senate District, none of the five representatives of those localities live in the 9th District and thus cannot run for the seat.

Sen. Peterson said she has “nobody in mind” for the seat.

With her announcement, the General Assembly is guaranteed to have at least two new members next year. Rep. Harold “Jack” Peterman, R-Milford, said earlier this year he is not seeking another term.

Sen. Peterson served as an aide at Legislative Hall in 1969 and spent 28 years with the Department of Labor before departing in 2001. She won the seat after Sen. Thomas Sharp retired in 2002.

On Tuesday Sen. Peterson made her announcement with several family members in the chamber, including her wife, Vikki Bandy. The two were the first couple to have their civil union converted to marriage after same-sex marriage was allowed by state law on July 1, 2013.

“This place has been like a second home to me for nearly 50 years,” Sen. Peterson said on the floor.