The Democrats now have a divisive Senate primary on their hands in New Jersey, with Congressman Rob Andrews announcing that he is challenging incumbent Frank Lautenberg in the June primary.

Andrews' big issue will probably be Lautenberg's age — the Senator is 84 years old, and polls have shown opposition to him getting another term because of it. On the other hand, expect Lautenberg to hit Andrews for his 2002 vote to authorize the Iraq War, and to have the whole might of the New Jersey Democratic machinery at his back.

By the way, this primary could be the biggest challenge Lautenberg faces this year — as we laid out last week, the Republican candidates aren't exactly an impressive bunch. So whoever wins, this might still be a safe Democratic seat anyway.