Edward Kennedy's two sons and his widow, Vicki Kennedy, are at odds over the late senator's legacy and the handling of the $71 million institute that bears his name.

According to Boston.com, the conflict is centered around the construction and governance of the Edward M. Kennedy Institute for the US Senate.

Vicki Kennedy has also become a source of contention among some extended family members over the institute's presence in the Kennedy family's Hyannis Port compound. The institute, which took possession of the original mansion and the lawn, is now charging a rental fee to the remaining family members who own property there for use of the lawn.

According to an unnamed family friend, the project faces potential cost overruns and the senator's sons, Edward M. Kenndy Jr. and Patrick Kennedy are convinced their stepmother is bungling the efforts to create what could potentially be a monument to Kennedy's career in the US Senate.

They also believe that she is relying too much on a small group of the senator's friends and supporters and are upset that the institute's board has failed to fulfill their request for a full financial accounting of the ongoing construction project and for strategic planning documents detailing how they plan to operate the institute.

Lee Fentress is a longtime friend of Vicki Kennedy who now chairs the board. He said that Kennedy Jr. conveyed his concerns to him and other members, but that the board's dealings are transparent. He also said that the budget is under control and that fundraising is strong.

“He and I have had conversations about his concerns about the size and scope of the project," he said. “We have agreed to meet in the coming days to go over all this. I am convinced that once we do this, his commitments to the institution will be reinforced."

Fentress also defended Vicki Kennedy, who declined to be interviewed  for the Globe article, saying that she is carrying on the work that she and the senator began in 2002 to develop a vision for the institute.

“He treasured her counsel," Fentress said. “He trusted her judgment and instincts. She was his right hand and partner in the very true sense. . . The board of the institute unanimously agrees with his judgment of Vicki. She is a tireless and passionate advocate for the institute. We are fortunate to have her."

The sons also refused to comment, but according to Boston.com, their decision to authorize a friend to share their concerns is highly unusual for members of a political family who have always strived to avoid the public airing of internal disputes.

The family is not allowed to use the house, which has sat unused since the senator's death in 2009. Institute officials explained that allowing the family to freely use the house and property would jeopardize its tax-exempt nonprofit status.

According to Boston.com, the late senator envisioned the institute as a center to educate the public, students, educators, new senators, and Senate staff on the US Senate. The building will be owned by the University of Massachusetts, with construction managed by the UMass Building Authority.