"I'll be the first to admit: I'm no Cory Booker," Holt says in the video, standing in a college lecture hall.
Instead, Holt introduces himself as "a teacher, a scientist," and touts his support for tougher gun laws, environmental restrictions, and closing tax loopholes for corporations.
"I'm going to beat Cory Booker and win this campaign the same way I beat Watson in Jeopardy! - one answer at a time," Holt's two-minute video concludes.
Holt, Pallone, Booker, and Assembly Speaker Sheila Oliver are all competing to fill the term of the late Sen. Frank R. Lautenberg, who died June 3.
Polls indicate Booker is the heavy favorite, but Holt, in a conference call with reporters, downplayed the challenge.
"This isn't even the toughest race of my career," he said. "I intend to win, I expect to win."
Booker, meanwhile, is winning quick endorsements from party leaders. The South Jersey Democrats who formally endorsed him Wednesday praised his political views and pragmatism - and also hoped that he'd return the favor in November, when Democrats are trying to keep control of the Legislature in the face of Gov. Christie's reelection bid.
Booker gives Democrats the "greatest opportunity . . . in November to make sure we maintain a Democratic Legislature [and he] is as equally committed to that as we are to him," Assembly Majority Leader Louis Greenwald (D., Camden) said at a news conference in Deptford.
Greenwald and Senate President Stephen Sweeney (D., Gloucester) each said Booker embodies Democratic ideals and will work across party lines.
Booker vowed to help them in turn after October's special Senate election.
"I will be, God willing, a sitting United States senator, sitting here again in South Jersey, battling with the people I'm standing with right now to preserve and advance in the [state] Senate and the Assembly, to push for change at the state level," he said.
Booker's new endorsements came from top party officials in New Jersey's seven southernmost counties. The backing was no surprise - George E. Norcross III, South Jersey's most influential Democrat, had already endorsed Booker. Norcross is comanaging partner of the company that owns The Inquirer.
Also Wednesday, Pallone unveiled backing from a slew of top Democrats in Middlesex County, part of his district in Central New Jersey and the Shore.
Contact Jonathan Tamari at email@example.com or follow on Twitter @JonathanTamari. Read his blog 'Capitol Inq' at www.inquirer.com/CapitolInq.