By Beth Germano

BOSTON (CBS) – Bowing to growing pressure from fellow senators to step down, former Senate President Stanley Rosenberg resigned from the elected position he’s held for more than 27 years.

One sentence “I hereby resign” was delivered to the clerk Thursday afternoon, but it spoke volumes of the effect of a Senate Ethics Committee investigation which concluded he failed to protect the Senate from his estranged husband Bryon Hefner he knew was “volatile” and “abusive”.

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Former Massachusetts Senate President Stan Rosenberg. (WBZ-TV)

Governor Charlie Baker told WBZ-TV’s Jon Keller Thursday before the announcement that Rosenberg should step down.

“He made very clear to people after there were some modest incidents a few years ago involving Bryon Hefner that there was a bright line, a firewall, between his personal life and his professional life,” Baker said.

“And it’s pretty clear based on the results of that report that that’s not true and it’s also pretty clear that Bryon Hefner created a lot of chaos, consternation, anxiety, and in some cases, abused people who either did business with the Senate or worked in the Senate and I think if you sort of add that all up, it says to me that the Senate president made a commitment to his team and he violated that commitment.”

The Ethics Committee concluded Rosenberg didn’t violate Senate rules but demonstrated a failure of leadership by not intervening despite knowledge Hefner racially and sexually assaulted people that work in and around the State House.

“I hope one of the products of all this is an environment where people believe they can come forward,” Baker said.

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After announcing his resignation, Rosenberg issued a statement Thursday afternoon, saying he deeply regrets “the difficulties that this situation has created for the members, the staff and the institution of the Senate.”

Read: Rosenberg’s Full Statement (.pdf)

In a statement read by Senate President Harriette Chandler, the Senate vowed to change a culture of fear. “We want to say to victims, staff and all those affected, we are sorry for what you have been through, you deserve better and we must do better.”

A close ally, democratic Senator Jamie Eldridge, also called for Rosenberg’s resignation and says the impact has been profound. “I think it’s created uncertainty, and one of the biggest impacts is staffers and those assaulted and harassed generally felt unsafe in the work environment,” Eldridge said.

Massachusetts Gov. Charlie Baker. (WBZ-TV)

Hefner faces 10 felony counts for allegedly sexually assaulted and harassing four men who claim he then boasted of his access to Senate business. Even though the ethics committee didn’t call for Rosenberg to step down members say their report is an important record of what happened.

“That is an action that is used only in the rarest of instances done by the voters they are sent to represent,” said Senate Minority Leader Bruce Tarr. “We were willing to give Senator Rosenberg an opportunity to do the right thing and he did it.”

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The resignation takes affect at 5:00 p.m. on Friday.

Beth Germano