Newton Mayor Warren announces US Senate candidacy

"As a Democrat, I believe in the core values of creating opportunity for all Americans, protecting our most vulnerable," Warren said as he sat on the front lawn of his childhood home — which he now owns.

"Yes, we need to cut government spending, but we cannot let a crisis born of fiscal mismanagement destroy all that we stand for as Americans," the mayor added, repeatedly emphasizing the concept of "shared values" and "shared responsibility."

Warren, 40, was careful to pay homage to the 51-year-old Brown, who upset the state and national political establishments in January 2010 when he staged a come-from-behind victory over Democrat Martha Coakley to seize the US Senate seat held for nearly a half-century by the late Edward M. Kennedy.

Polls have since consistently shown Brown as the most popular politician in the state, and no incumbent Democrat before Warren has stepped forward to challenge him. Somerville activist Bob Massie and City Year co-founder Alan Khazei have previously announced their candidacies.

"I believe Scott Brown is an honorable man, but he has not been the independent voice in the Senate that so many expected him to be. He's voted 87 percent of the time with his national Republican leaders," said Warren.

Brown spokesman Eric Fehrnstrom said: "It looks like there will be a very crowded Democratic primary, but the election is still 18 months away and Scott Brown's focus in the near term will continue to be on creating jobs and reducing spending."

Federal election records show no campaign organization for Warren, but aides said the necessary paperwork was filed today, ahead of required deadlines.

Deborah Shah, who will serve as campaign manager after holding a similar job for the mayoral campaign, said Warren began raising money in a bank account he opened late last week, and produced the video during the past 10 days with Putnam Partners. The firm produced Barack Obama's 30-minute address to the nation amid his successful 2008 campaign for the presidency.

"The campaign will pay for the video when it's invoiced," said Shah. "It was produced in the past 10 days and I expect they're on a normal 30-day billing cycle, so I would expect a bill any day now."

Warren was elected mayor in November 2009, the first African-American popularly elected as mayor in the state. There currently are no blacks in the US Senate.

His relatively brief, 16-month tenure has prompted some complaint from city residents who believe he should serve out his term before seeking higher office.

US Representative Barney Frank, a fellow Democrat from Newton, publicly declared that Warren should not run, telling Politico, "I think the timing is bad for him."

In his announcement video, though, the mayor cast his decision as an extension of the public service commitment that has permeated his life.

He spoke of his father's prior military service, as well as his own decision to volunteer for the US Navy in the aftermath of the 9/11 terrorist attack. Warren ended up doing a combat tour in Iraq as an intelligence specialist.

Warren also served in the Clinton administration as a special assistant in the Office of Cabinet Affairs, as well as an aide to Senator John Kerry — including as trip director during his 2004 presidential campaign — and as the New England regional director of the Federal Emergency Management Agency.

He graduated from both Boston College and Suffolk University Law School. He and his wife, Tassy, have a daughter, Abigail.

Warren plans a formal speech tomorrow morning.

Glen Johnson can be reached at johnson@globe.com. Follow him on Twitter @globeglen.