“Rob’s sudden return to the public eye is deeply troubling to me,” wrote Jennifer Willoughby, who was married to Mr. Porter from 2009 to 2013, “because he has yet to candidly address the thing that should — that must — come first: his personal conduct during his two marriages.”

In a blog post describing her marriage in which she did not identify Mr. Porter by name, Ms. Willoughby accused him of pulling her, “naked and dripping,” from the shower to yell at her and said that she had filed a protective order with the police after he punched in the glass on the front door of her house while she was locked inside. She has also detailed other emotional and verbal abuse.

Mr. Porter’s other former wife, Colbie Holderness, has described their relationship as “verbally, emotionally and physically abusive.” She has shared with the press photographs of herself with a black eye and a swollen cheekbone, which Mr. Porter said at the time were misleading. He has denied all allegations of abuse in the past, and did not return calls or respond to text messages on Thursday.

The power of Ms. Willoughby’s response to Mr. Porter’s re-emergence might be in its measured manner, in which she weighs how one should be allowed to return to public service after a scandal involving abuse.

Mr. Porter, she wrote, should not be “forever barred from using his considerable professional skills and knowledge to make a contribution to our society.” She added that she had no agenda for Mr. Porter’s future and outlined ways that fallen men might succeed in rehabilitating themselves.