Senator Frank Lautenberg, the New Jersey Democrat who at 89 is the U.S. Senate’s oldest member, said on Thursday that he will not seek re-election next year.

Newark Mayor Cory Booker, a fellow Democrat, is seen as a front-runner to replace Lautenberg, a self-made multimillionaire businessman who became a leading liberal voice in the Senate.

In a statement, Lautenberg offered no reason for his decision to retire from Congress, but vowed to keep working in the Senate for constituents until his term ends in January 2015.

“While I may not be seeking re-election, there is plenty of work to do before the end of this term and I’m going to keep fighting as hard as ever for the people of New Jersey in the U.S. Senate,” he said.

“This is not the end of anything, but rather the beginning of a two-year mission to pass new gun safety laws, protect children from toxic chemicals, and create more opportunities for working families in New Jersey,” he said.

He was first elected to the Senate in 1982, running after incumbent Democrat Harrison Williams quit in a bribery scandal.

Lautenberg previously retired from the Senate in 2000, saying he was tired of chasing campaign contributions. But in 2002 he came out of political retirement at age 78, again helping the Democrats retain a seat in the chamber after Senator Robert Torricelli dropped his re-election bid amid corruption charges involving improper gifts from a businessman.

Lautenberg was re-elected in 2008 at age 84.

The World War Two veteran was a co-founder, former chairman and chief executive of the payroll services company Automatic Data Processing.

(Reuters)