From a strictly odds-based standpoint, Booker's move makes complete sense. Lautenberg hasn't said yet whether he is going to retire, but there is a strong possibility that he will. He is, after all, 89 years old. So, if you're Booker, your choice was between challenging an immensely popular incumbent or running for what, in all likelihood, will be an open Senate seat in a Democratic-tilting state.
Booker's decision disappointed many Democrats hoping for a blue-chip recruit to take on Christie. Beyond him, there were no other obvious candidates for Democrats. Several other names that surfaced as possibilities -- state Senate President Stephen Sweeney and former governor Richard Codey -- took themselves out of the running in the last few days.
With the top tier (and, really, second tier) running dry, Democratic leaders coalesced this week around Barbara Buono, a little-known state senator who polls show is trailing Christie by a wide margin.
"Barbara Buono understands the challenges facing New Jersey's middle-class families because she's lived through them," said Democratic Governors Association Chairman Peter Shumlin in a statement Tuesday.
Republicans, naturally, took a different view of Democrats' decision to rally around Buono.
“After failing to recruit their first, second, third or fourth choice candidates into the campaign for governor, Democrats have finally settled on state senator Barbara Buono," said Republican Governors Association spokesman Mike Schrimpf.
It's certainly too early to count Buono out of the contest, given the state's Democratic tilt. But it's fair to call her a long-shot at this point.
A recent Quinnipiac University survey showed Buono trailing Christie by 41 points. Not only that but the same poll showed that the vast majority of voters don't know her. Eighty-two percent of voters said they didn't know enough about Buono to have an opinion about the state senator. That's a major problem in New Jersey, which doesn't have its own media market and is covered by two of the most expensive markets -- New York City and Philadelphia -- in the country.
Raising her own profile will only be part of Buono's challenge. Buono's other major task will be to reduce Christie's popularity. Christie is more popular than almost every other governor in the country right now thanks to his handling of the aftermath of Hurricane Sandy, which devastated parts of the Garden State.
Christie's handling of Sandy won him wide praise from Garden State voters. In the Quinnipiac poll, 94 percent of New Jersey voters rated his response as either excellent or good. And they really liked the tongue-lashing he directed at House Speaker John Boehner (R-Ohio) for refusing to schedule a vote sooner on a Sandy aid measure.
At this point, Christie's support extends well beyond Republicans. In the Quinnipiac poll, majorities of Democrats (56 percent) and independents (78 percent) said they approve of the governor's job performance.
A lot can happen between now and November. But for now, Christie's is in very sound political shape. If he keeps it up, Democrats will be reminded the hard way about how much timing matters in politics.