He will be facing a challenge in the primaries. There are two candidates who are running against him.
The more serious is Congressman Rob Andrews, who many thought would be picked by Corzine when he became Governor and needed to fill his set. (Corzine did good picking Menendez) One issue is that Andrews was one of the co-sponsors, Co-authors (?) of the IWR. He is taking a quote out of context (a la Bill Clinton to say that Lautenberg, who was not in the Senate for the vote once supported the war. I saw him speak once at a rally for Democrats when Menendez was running in 2006. Both he and Lautenberg spoke. He is very polished and speaks well and was clearly a favorite of the party. One difference between him and Lautenberg was how they interacted with people - Andrews was competent and responsive in a WJC/JRE way. Lautenberg was a storyteller whose life related to his politics. A couple in their 50s came up and told him that there families also came from Patterson. After the usual Jewish geography where they found many likely connections, they mentioned the silk factories that Patterson was long ago famous for. What followed was a fascinating story about the Senator's family.
His dad worked in the silk factory and he remembered his dad telling him, as he pushed him to do well in his school work, that he (Frank) needed to work hard and get an education that would allow him to work in a place where his life would not be shortened by exposure to things like the air in the silk factory. He spoke of how his dad would show him small pieces of thread that had fallen on his clothes, telling him that it was hard to breathe with that in the air. He then spoke of how his dad and others died young - I think he said that his dad died at 45. He spoke of how he joined the service for WWII and then got a college degree.
This then spoke of how that background was why he stood up for unions, for environmental initiatives etc. This was all off the cuff with a large part of the crowd of county Democrats standing in a semicircle around him. He was just a very good guy. (This was about September 2006 - so the details may be off -but it does convey my impression.
The other challenger is the Mayor of Morristown. Cresitello was the Democratic major back in the 1970s - then he sounded progressive - though his idea to merge too low tax towns (many corporate headquarters) to the high tax Morristown never - for some reason interested the other two towns!. After he lost, he was on and off the town council - even as a Republican for a while during a period where he annoyed too many Democrats. He gained notoriety on immigration - when he spoke at a America for Americans (or something like that rally)
http://symsess.blogspot.com/2007/08/mayor-donald-cresitellos-speech.html He actually came close to not being on the ballot because he just barely had the 1000 signatures needed.
The part is supposedly angry at Andrews for challenging and all the official Democrats are supporting Lautenberg. (Cresitello is - I think just considered a nuisance.