Randy Evans, the lawyer who represented Hastert in the Foley case, said that episode made it clear that congressional leaders no longer can plead the "'I don't know' defense.'"
He said the October conversation between Massa's chief of staff and Pelosi's staff member should have been reported to the ethics committee even if it just focused on allegations of abusive conduct that was not sexual.
"The ethics committee removed the ability to have blind indifference," Evans said. "You can't just look the other way and not be focused on learning more. There's an affirmative responsibility to find out more, ask questions, determine the scope and take appropriate action."
Massa has acknowledged in a TV interview that he had groped a staff member, but he described it as tickling, not sexual behavior.
That remark became a late-night punch line.
At the White House Correspondents' Association dinner, President Barack Obama played the case for chuckles.
"Politics can be a tough business," he said, "but there are times where you just can't help but laugh.
"You know what really tickles me? Eric Massa."