Rep. Robert E. Andrews defended Newark Mayor Cory Booker’s primary challenge to his fellow New Jersey Democrat, Sen. Frank R. Lautenberg, on Tuesday.

“I think he’s tried to be respectful of the senator’s choice, but made it clear he’d like to serve in the Senate and I think that’s very legitimate,” Andrews told CQ Roll Call.

Andrews knows what it’s like to be in Booker’s position. In 2008, he challenged Lautenberg in the Democratic primary; he lost by a whopping 24-point margin.

Booker announced his intention to explore a bid for Lautenberg’s seat late last year, when speculation had already started over whether the 89-year-old senator would run again in 2014.

“I don’t think he’s made that decision yet,” Andrews said about Lautenberg. “Once he’s made that decision, other people will make theirs, including Mayor Booker. I think it’s in the very early stages of formation.”

Much of the state Democratic establishment has angrily piled onto Booker over the past two months for not giving Lautenberg ample space to retire gracefully.

But Andrews was not nearly as tough on Booker as others in his delegation.

For example, fellow Democratic Rep. Bill Pascrell Jr. recently said, “My friend Frank Lautenberg is a dog. I mean he ain’t gonna lay down for anybody.”

CQ Roll Call rates this race as Safe Democratic.