Frank Lowenstein got married in April, became a father in June and works 13-hour shifts as a foreign policy adviser for Sen. John F. Kerry -- most recently in helping prepare the presidential candidate for last night's foreign policy debate.

"It's a perfect storm of events that has conspired to deprive me of sleep," Lowenstein said on a day when he walked into Kerry-Edwards headquarters at 8:30 a.m. and would not leave until 4 the following morning.

But what really keeps Lowenstein working into the night is something more subtle than a storm. It is the memory of his murdered father, Allard Lowenstein, the iconoclastic civil rights and antiwar leader. During the 1960s and 1970s, Allard Lowenstein inspired thousands of Democrats, including Kerry. Now Frank, in turn, said the Massachusetts senator has inspired him.

"After my dad died, we felt a powerful sense of loyalty to the people who remembered him," said Lowenstein, 37. Over the years, Kerry has praised the one-term New York congressman. In a 1970 interview, Kerry said that by protesting the Vietnam War, "I'm just going to be one man adding to the work of men like Lowenstein."

Today, Frank Lowenstein says, "It has come full circle now. I'm just one of the people trying to help John Kerry."

The link between father and son is unmistakable. Frank has his father's profile, his hairline, his mischievous laugh and his habit of carrying around old newspapers in case he missed yesterday's news. Kerry, who in a statement described the younger Lowenstein's presence on the campaign as "an honor," said, "Frank has the gift of his father's social conscience and passion. . . . He's got that same unshakeable faith that he's in this for a reason that's bigger than any of us."

Kerry said he first heard Allard Lowenstein speak when he was a junior at Yale. The New York activist urged the students to help African Americans in Alabama and Mississippi attain equal rights.

"No single speech stands out more in my memory than Allard Lowenstein's visit to campus," Kerry said. "You felt a responsibility to get up and do something, and you believed in your ability as an individual to actually make a difference. I can still feel the idealism of that moment."

It is that intangible that Frank hopes to keep alive, the spirit of a man who in 1980 was cut down by seven shots fired from a 9mm pistol. A former protege with a history of mental problems killed Allard Lowenstein in his New York law office. Frank, the oldest of three children, was 12 years old. He wondered why he hadn't been there that day to knock the gun from the assailant's hand.

"How do you make peace with that?" he asked.

He looks for the answer in his daughter's smile: "A little bit of my dad lives on in Addie, and in the campaign."

Frank Graham Lowenstein -- named after his father's mentor, Frank Graham, a liberal senator from North Carolina -- was born in New York in 1967. When his mother called his father to say she was in labor, she could hear Martin Luther King Jr. giving a speech in the background. The doctor said the labor would not be brief, so Allard Lowenstein flew to the University of Maryland for a "Dump Johnson" rally and returned at 1 a.m. -- after his son was born. (Family lore has it that he bribed his way into the hospital after hours with Devil Dogs, the staple of his diet.)

Frank's stepfather, Nick Littlefield, who worked with Allard Lowenstein and Kerry in the early 1970s to register young voters said that "the two of them were extraordinary back-to-back public speakers." Littlefield, a former senior aide to Sen. Edward M. Kennedy (D-Mass.), said, "Frank has this passion for the underdog, which he got genetically from his father."

From the time he was 8, Frank Lowenstein stood on street corners in Brooklyn, handing out leaflets for his father. The family was so immersed in politics, he said, "my little sister used to introduce herself as 'Katharine Eleanor Lowenstein for Congress.' "

After attending Yale and Boston College Law School, Frank worked for a Boston law firm. One day, at a Democratic fundraiser, he met Sen. Christopher J. Dodd (D-Conn.), who had known his father. Lowenstein recalled their conversation:

"So, Frank, what do you do?"

"I'm selling big shopping centers in California."

Dodd laughed and said: "Man, your dad would be so ashamed of you."

Walking back to his law firm, Lowenstein decided to resign. In the spring of 2003, he volunteered for the Kerry campaign. His mother, Jenny Littlefield, a psychiatric social worker, said Frank laid out all of his clothes on the front lawn, consigning his law-firm suits to her basement for storage.

Suddenly without a source of income, he bunked at his uncle's house in Washington. He and Rand Beers, Kerry's national security adviser, worked with one other volunteer out of Beers's bedroom -- their desk in one corner, Beers's bed in the other.

Today, Lowenstein works for the Democratic National Committee and is advising the Kerry campaign. He is part of the nine-person foreign policy team at Kerry headquarters. A picture of a snarling Vice President Cheney decorates their cubicles, as does a photo of President Bush wearing a cowboy hat, captioned "YEE-HA is not a foreign policy."

Beers described Lowenstein as their "project manager." He specializes in issues relating to terrorism, nonproliferation, homeland security and intelligence reform. James P. Rubin, a senior campaign adviser, said Lowenstein stands out, because "often the most committed are also the most intense. Unlike some, Frank's cheerful."

Lowenstein said he thinks his father would be proud, although he is not following lock step in his footsteps: "My dad was all about human rights, but after 9/11, I don't always think human rights first. I think security."

He is driven by the desire to right a wrong, Lowenstein said; murder should not go unpunished.

"I thought we had to go get the bad guys," Lowenstein said, his father's passion in his eyes. "There's some element of vengeance."

Frank Lowenstein was immersed in politics as the son of a civil rights leader.