Cahill defends taking questioned campaign donations

“Unless I am personally wealthy, which I am not, or there is public financing, which there is not, you are forced to ask people and accept contributions, and it’s up to us, as politicians, to make sure there is no commingling, there is no crossover,’’ Cahill, an independent, told faculty and students at a forum at Suffolk Law School’s Rappaport Center for Law and Public Service.

Cahill said donations to his political account do not influence the decisions he makes as chairman of the state Pension Reserves Investment Management Board.

“We have a very tight wall, a very firm wall, between the political and the professional in the way we run our operations,’’ he said. “The folks at PRIM know nothing about what I do personally and what I do politically doesn’t influence my decisions at PRIM.’’

Cahill pointed to the board’s returns, which he said are in the top 10 percentile of state pension funds.

“The proof, in my mind, is in our returns and our results,’’ he said. “People who get business based on politics are not going to be able to perform and make you money — simple truth.’’

The Globe reported Sunday that Cahill had accepted more than 200 campaign donations from the officers of firms connected to a pension fund manager who has been allotted $500 million in state funds to invest since Cahill became state treasurer in 2003. The contributors shared a common connection: They or a relative worked for firms that handle the real estate holdings that Michael A. Ruane, a Boston investment manager, bought for his investors, including the state pension fund.

Cahill has been under fire for the donations from his two Republican rivals in the governor’s race. Cape Cod businessman Christy Mihos has said the contributions pose a “conflict of interest of the highest regard.’’ Former health care executive Charles D. Baker has said they reflect “a failure to be more transparent.’’

Yesterday, state Representative Karyn E. Polito, a Shrewsbury Republican who is running to replace Cahill as treasurer, said that if elected, she would require investment managers, underwriters, and other entities doing business with the Treasury or who seek to do business with the Treasury to disclose all political contributions their officers or senior managers made during the preceding 12 months.

“Our next state treasurer needs to insist on complete transparency and openness when it comes to the business practices of the Treasury itself, the Lottery, the pension fund, and all other operations,’’ she said in a statement.

At the Suffolk forum, Cahill also offered some of his harshest criticism yet of Baker, who was budget chief for governors William F. Weld and Paul Cellucci, accusing Baker of enabling massive cost overruns at the Big Dig and burdening the state with debt to pay for the project.

“He oversaw the Big Dig, which we are paying for today,’’ Cahill said. “As the [administration and finance] secretary, he can’t avoid it. He can’t tell everyone there were 50 people in the room. When you’re the A&F secretary, you are the governor’s chief budget writer. You are the governor’s CFO, which makes you practically the CFO of the entire state.’’

Baker spokesman Rick Gorka dismissed Cahill’s criticism. “Charlie was A&F secretary for four of those 24 years of the Big Dig, and the explosion in costs and how horrible it became was well after he left the administration,’’ Gorka said. “He was no longer part of the Big Dig.’’

Gorka said Baker had a “very strong record of reform,’’ and said, “Cahill is trying to deflect attention from his failed record of the last 3 1/2 years.’’

Cahill said he was raising the criticism to show that he, not Baker, is the real fiscal conservative in the governor’s race.

“Even though we both talk the same language, look at our records,’’ Cahill said. “Look at who has truly been a fiscal conservative.’’

Michael Levenson can be reached at mlevenson@globe.com.