William P. Monahan, a popular selectman who represented the “Old School” of Belmont politics, but whose business involvement with the Boston mob would tarnish his reputation, died on Friday, Oct. 31.

Monahan, who lived for 50 years in a modest Cross Street house, was 80.

Flags at all Belmont Municipal Buildings will be flown at half-staff in honor of  Monahan through Thursday morning.

Winning a seat on the board in 1978 on his fourth try for the office, Monahan was one of the last of the “Old School” Belmont politicians, where strong personalities – in the tradition of James Watson Flett who served four decades on the board – and the will of the Belmont Citizens’ Committee set town policy with little community interaction.

In fact, in 1978, Monahan was himself a victim of a long-standing Belmont tradition: the poison-pen letter delivered days before the Town Election, attempting to smear his reputation and politics.

Monahan, a no-nonsense, at times gruff, attorney who was born in West Roxbury and raised in South Boston, said his greatest responsibility on the board was to preserve the “small town” feel of Belmont, protecting it “against urbanization.” He was a leader in efforts to keep property tax rates low to allow “old timers” the ability to reside in their hometown during a time of increasing housing values.

He would use his conservative approach to town finances – Monahan was a loyal Republican – to question other’s “fiscal responsibility” on concerns of inadequate funding for capital projects and school buildings.

“It was a much more fiscally conservative town,” Monahan said in a 2002 Boston Globe interview when describing his hometown when he arrived in the mid-1960s.

In later years, Monahan sought to increase town revenue with the creation of a new hub on South Pleasant Street where new police and fire department headquarters would be adjacent to a commuter rail station with a 200-vehicle garage.

Monahan was known for “flying solo,” as reported in the weekly Belmont Citizen newspaper, using his Selectmen’s position to advocate citizens and neighborhoods. Many times, Monahan negotiating one-on-one with entities such as the city of Cambridge for Payson Park-area residents during the renovation of the nearby reservoir, then come before the board with the “solution.”

Monahan also gave private assistance on zoning issues to the leadership of the local Church of Jesus Christ of Latter-day Saints community during its successful effort to build a temple on Belmont Hill.

Residents soured on this approach, most notably when he appointed a four-member “committee” to privately negotiate a purchase agreement with O’Neill Properties for the Belmont Uplands. When brought before Town Meeting in 2001, the deal was criticized for its favorable terms to the developer while providing no guarantees to the town on revenue or environmental safeguards. The measure was voted down.

The state Attorney General also criticized the board for violating the state’s Open Meeting Laws during the multi-year settlement with McLean Hospital.

Changing town demographics and a more active – and liberal – population base would view Monahan’s approach to governing more critically. Many at the time contend Monahan’s defeat by Ann Paulsen in 1992 for an open State Representative seat had much to do with “newcomers” flexing their political muscle.

Monahan’s world view was brought out in the 2002 Globe interview when he said when he was first elected, “[i]t was fashionable, almost, for the mom to stay at home. It’s no longer fashionable, which, you know, I find extremely difficult to accept. I think the most important profession in the world is motherhood.”

Monahan made national news when he initiated a rally for Mitt Romney after the Belmont resident successfully rescued the Salt Lake City Winter Olympics. On a snowy day in March 2002, Monahan handed Romney a pair of running shoes and led the chant, “Run, Mitt, run,” referring to then possible Romney candidacy for Massachusetts governor.

But many residents took exception to the rally that used town resources to promote what they viewed as partisan political efforts, a charge Monahan would decry at a Selectmen’s meeting.

Many believe the negative impact of the rally and the Belmont Uplands proposal contributed greatly to his defeat for a 10th term by Paul Solomon in April 2002.

When asked the difference in Belmont between the time he was elected and his defeat, Monahan pointed to the “[l]ack of sense of community,” in the Globe interview.

“You know, sometimes you don’t speak to [your] next-door neighbors. We’re all so busy pursuing whatever our interests are. I think not just in town government, but I think in our world, there’s been a drastic reduction in the sense of the need for civility,” he said.

During his tenure, Monahan would serve as Selectmen chair from 1983-86, 1989, 1995-97 and 1999-2001. He was also a Town Meeting member from 1974 to 2002.

Soon after becoming governor, Romney appointed Monahan chairman of the state’s Civil Service Commission in July 2003 at a salary of $80,000.

Monahan abruptly resigned in August days after the Boston Globe revived a Dec. 1992 Belmont Citizen article that Monahan and a partner secured a $180,000, 10-year loan in 1980 from Gennaro “Jerry” Angiulo, a former New England mob underboss to purchase a bar in Boston’s theater district. The real estate firm that sold the bar to Monahan, Huntington Realty Trust, was later determined to be a front for the Angiulo’s illegal gambling enterprise.

Monahan said while knowing of Angiulo’s involvement in the mob; he told the Boston Globe at the time that “It was bad judgment. No serious harm came of it, but I never should have gotten involved in the thing.”

In 2009, Monahan sued Romney in federal court for wrongful termination without due process but the suit was dismissed.

While most people in town remember Monahan for this community service, the long-time Cross Street resident was a well-respected member of both the legal and academic world.

After serving in the US Coast Guard during the Korean War, Monahan matriculate at Boston State College, obtain a Masters Degree in counseling psychology from Boston College and a Juris Doctor from Suffolk University School of Law. He served 20 years as an assistant professor and later as an associate clinical professor of Psychiatry at Tufts University Medical School.

Monahan is survived by his wife, Edith J. Monahan (Mungovan). He is father to Julie Brady and her husband Brian of Belmont, Marianne Monahan MD and her husband Timothy Busler of Greenwich, Conn, Maureen and her husband Mark Bobbin MD of Belmont and William P Monahan Jr and his wife Kathleen Srock M.D. of Denver, Colo. His grandchildren are Brian, Marykate, John, Caroline, Connor, Teddy and Colleen. He was the brother of the late John J. Monahan and Mary Mahoney. He is also survived by many nieces and nephews.

A funeral Mass will be celebrated at St Josephs Church, 128 Common St., Belmont on Thursday, Nov. 6 at 9 a.m. Burial will be at Highland Meadow Cemetery in Belmont.

Donations may be made in his memory to the Wounded Warrior Project P.O. Box 758517 Topeka, Kansas 66675.