"We receive an average of 12,000 letters and e-mails a week," says Elkis, who along with her staff of five acts as the senator's eyes and ears in New Jersey's seven southernmost counties.
"People just walk up [during public events] and ask for help with an issue, or clarification of a matter, or just to tell you what they think," she says. "When there is a burning issue [like Obamacare] my office can get about 50 calls a day."
The tasks seem unlikely to land her a guest spot on, say, Morning Joe. But they do offer deep satisfactions for a self-described Jersey girl who knows how to network.
Elkis is a veteran of the time when the divide between Democrats and Republicans was less . . . daunting. An era when the parties frequently got things done together.
"I've had a working relationship with Karin for 20 years, and it's been nothing but positive," says Rep. Frank LoBiondo (R., Atlantic), whose conservative affinities would seem to make him an unlikely collaborator with a Democratic senator's office.
But he and Elkis have found common ground in protecting New Jersey's environment.
"We have a relationship of trust," LoBiondo says. "It's about, 'Let's get on the same page.' "
Elkis grew up as the oldest of four children in Woodbury, where she managed the Woodbury High football team before graduating from the school in 1974.
Her father, Preston Elkis, was a dentist; her mother, Nancy Cohen Elkis, in 1974 became the first woman elected to the City Council.
Back then, Democrats rarely won office anywhere in Gloucester County. But when Nancy Elkis died in 1996 after a 15-year battle with cancer, Republicans and Democrats alike praised her record of community service.
"We were Democrats, but it wasn't a capital D," recalls Karin Elkis, who is married to Steven D. Weinstein, the general counsel for Rowan University.
"What you were doing for others was more important."
Sounds rather warm and fuzzy for someone who has spent three decades working closely with elected officials whom few if any would describe as cuddly. Or particularly bipartisan.
Fresh out of Tulane with a master's degree in social work, Elkis got hired as an aide to Assemblyman Martin Herman (D., Gloucester) in 1980. She stayed with his Trenton office for three years.
"After working for Marty Herman," she says, "you could do it all. You had to be in on time, you had to stay late, and you had to be on top of everything."
She went on to spend 17 years running Frank Lautenberg's South Jersey office during his first stint in the Senate, then did that job for his short-term successor, Jon Corzine. After Corzine resigned to run for governor, Menendez hired Elkis in 2006.
She has been his South Jersey point person ever since.
"Karin is a superstar. That's really the appropriate word," Menendez tells me by phone from D.C.
"She's a hard worker, with deep knowledge [of local communities], and she doesn't just use that network to promote my views. She's a problem-solver."
Elkis says she hopes to keep working "as long as possible . . . as long as I'm able.
"I've spent my entire career working to make our area a better place to live," she adds. "And I don't think I'll ever stop."