WASHINGTON - Amid a presidential campaign marked by fury and resentment, Sen. Cory Booker wants to alter the tone as he steps back into the national limelight.

The New Jersey Democrat is launching a book Tuesday that he hopes will serve as a tonic for the current civic mood and inspire a sense of unity.

"We definitely are seeing in our politics and in our civic spaces divisiveness being heralded," Booker said in an interview. "I think that the true character of our country is really about empathy and compassion."

The book - United - is full of his trademark grand themes and calls for positivity and cooperation, even as it describes harrowing scenes from his adopted home city, Newark.

The release, Booker's promotional tour, and his campaigning to help Hillary Clinton mark a return to the spotlight for a longtime political celebrity who has largely kept a low profile in his first two years in the Senate.

In recent weeks, Booker has been to Iowa, New Hampshire, and South Carolina to stump for Clinton. This weekend, he heads to Nevada, where he will represent her at one event that is slated to also feature her Democratic rival, Bernie Sanders.

United was planned well before the rise of Donald Trump, but its publication comes just a week after Trump and Sanders scored massive primary victories in New Hampshire by channeling the anger of people who feel left behind by economic and political forces.

It also arrives as Booker's name has become fodder in early chatter about potential vice presidential nominees. For many - including President Obama - books outlining a political philosophy have been a part of the climb to national office.

Booker, 46, dismissed such "hypotheticals" and said no one in the Clinton camp has discussed that idea with him.

"My focus is twofold right now: serving the state of New Jersey and working hard to get Hillary Clinton elected," he said.

Booker arrived in the Senate with a national name that resonated well beyond politics (he was among the celebrities who appeared on The Colbert Report finale), and he sounded ready to use that platform and reach.

"I plan on stepping out more," Booker said. "I'm tired and frustrated by the hyper-divisiveness in our country."

United contains no major scoops (he makes little mention of political figures or campaigns), and no blockbuster revelations about his private life.

The closest to either are when Booker, who is single, briefly mentions falling in love with a woman he met in 1996, and when he offers a mea culpa for the brash attitude he took to the Newark City Council.

"I was a jerk at times," Booker said. "I never said that publicly before."

Laced with biblical references, quotes from the Rev. Dr. Martin Luther King Jr., Albert Einstein, Mohandas Gandhi, the Dalai Lama, and others, along with Booker's own brand of uplifting discourse, the book calls on Americans to embrace the idea that they are all connected, and to take action to help one another thrive.

"A united country is an enduring struggle," Booker writes. He describes how his father told him to be like a thermostat - setting the temperature - rather than a thermometer, simply reflecting it.

His goal, he said, was to "celebrate the values of interdependency - of the understanding that we share a common destiny."

United blends his biography and most famous exploits in Newark with an ode to people who tried to improve the city and a call for action on his dearest policy issues, illustrated through people he met there.

Booker uses chapters to urge criminal justice reform, help for the working poor, and care for the environment, particularly in cities scarred by industrial pasts.

Much of the book features well-known parts of Booker lore (moving to the drug-infested Brick Towers housing complex after Yale Law School, cradling a young Newark man as he died from a shooting), and lines familiar to anyone who has heard his speeches. ("The lines that divide us are nowhere near as strong as the ties that bind us.")

The book, though, represents a chance to reach a broader audience.

And Booker has filled out some of those familiar stories with interviews with people involved.

For a chapter about Hassan Washington - a Brick Towers resident who wound up selling drugs and shot dead - the senator found the young man's father.

The father had gone to prison for murder, and then saw Washington's mother spiral into drug addiction. To Booker, the story shows how actions can reverberate for generations, and illustrates the different paths for those who have a supportive community (as his own father did) and those who don't.

But he also offers a positive example, describing how the civil rights marches in Selma, Ala., inspired two New Jersey lawyers to aid a nonprofit that would then help Booker's parents move to affluent Harrington Park, despite attempts to keep the black family out.

It's an example, Booker said in the interview, of how "small acts of kindness" can change lives.

From Harrington Park, Booker has enjoyed a stunning rise: Stanford, Rhodes scholar, Yale Law, Newark mayor, U.S. senator.

And now, author wading into the national debate.

Booker will be promoting his book at the Philadelphia Free Library's central branch March 1.

@JonathanTamari