He addressed the odds in a conference call with reporters, in which he touted his own voting record and characterized himself as the "person of substance in the race," but avoided direct attacks on Booker.

"I've been in tough campaigns. I've been in campaigns where conventional wisdom says the other guy will win. I've been in campaigns where the party organization has looked the other way or, on occasion, weighed in in the other way. And I've won and I've won and I've won," he said.

The most recent poll of the Democratic field, out from Rasmussen this week, showed Booker gaining 54 percent support to Holt's 11 percent and Rep. Frank Pallone's (D) 8 percent. Whoever wins the Democratic nomination is heavily favored to keep the seat left open by Sen. Frank Lautenberg's (D) death.

Holt enters the race at a financial disadvantage to Pallone, a prolific fundraiser who had $3.4 million in his war chest at the close of the last reporting period. Holt didn't have details on how his early fundraising push is going, and wouldn't estimate a number he plans to raise, saying only he plans to bring in "what I need."

But Holt expressed confidence in his ability to nab the nomination in the end.

"Can I win this race? Absolutely. This isn't even the toughest race of my career. I'm in this to win, I expect to win, I intend to win."

This early in the campaign, however, Holt seemed wary of directly criticizing his opponents. "I'm not talking about negatives," he told a reporter when asked about Booker.

But he did assert in a veiled knock on Booker's high-profile connections and popularity that "the primary in August is not going to be about celebrity.

"In fact, it can't be about celebrity. Just try to imagine what the campaign will be where celebrity would make the difference," he said.

The call came with the launch of a new Web video in which Holt did implicitly criticize Booker's celebrity, a line of attack likely to play prominently with Booker's opponents, as some critics have questioned whether the Newark Mayor is more flash than substance.

"I’ll be the first to admit: I’m no Cory Booker," Holt says in the video. "I don’t have a million Twitter followers, I’ve never run into a burning building, and I’m not friends with Mark Zuckerberg — though I did like him on Facebook."

In the video, Holt goes on to argue for his candidacy as an advocate of "good progressive policy," noting votes against the war in Iraq and "unwarranted spying on Americans" as well as his 100 percent record from the League of Conservation Voters.

Watch the video: