The state Senate on Wednesday returned to a fierce debate over a question almost as old as domesticated animals and the law: who should be held liable when somebody’s dog bites a person?

To make his point, one senator read graphic courtroom testimony from a dog-bite victim’s mother. Another demanded to know whether lawmakers would defend the rights of humans or animals.

Two years after Maryland’s highest court effectively declared any pit bull to be an inherently dangerous animal whose owner could be held liable for its attack, the legislature has divided into two basic camps.

Some lawmakers, particularly in the Senate, believe the full weight of responsibility should rest with the owner, regardless of the breed of pet or most circumstances surrounding the dog’s attack. Critics see that position as something like strict liability – which would mean there is no justifiable defense for damages inflicted by the animal.

Others, particularly in the House of Delegates, believe a pet owner should not be held responsible if he or she had no previous indication that the dog might attack someone – a position critics say is like endorsing the “one-free-bite” rule.

The two sides have been battling each other since the Court of Appeals, in its April 2012 Tracey v. Solesky decision, held that pet owners and landlords could be held liable for injuries inflicted by a dog that they knew or should have known was vicious. The high court, after sifting through medical and veterinary literature, also held that pit bulls posed an inherent danger because of their combative instincts and their powerful ability to inflict damage. Critics of the ruling said the decision cast a stigma over pit bulls, which started turning up in shelters in greater numbers, and caused some landlords to order pit bull owners to give up pets or move out.

On Wednesday, the debate was renewed as the Senate considered a bill sponsored by Sen. Brian E. Frosh (D-Montgomery).

Frosh, who chairs the Senate’s Judicial Proceedings Committee, said he had previously leaned toward the stricter terms of liability. But after the Senate passed similar measures that later died in the House of Delegates, Frosh said that this time he was sponsoring a bill that he characterized as a compromise.

Under Frosh’s bill, the owner of a dog that bit someone would be presumed to be responsible for damages because he or she knew or should have known the dog was dangerous, regardless of the dog’s breed. But Frosh’s bill would also allow the owner to neutralize that presumption by presenting evidence that the dog had been docile.

“It shifts the burden to the dog owner,” Frosh said.

But critics said that in practice, Frosh’s bill would still force victims to try to prove that a dog was vicious. Some argued that if an owner should be held liable for the dog’s behavior under almost any circumstances.

“This is not a bill that’s good for victims,” said Sen. Robert A. Zirkin (D-Baltimore County), who attempted to amend Frosh’s bill to shift the responsibility to the dog’s owner for any bite. He also read some testimony from the mother of Dominic Salesky, who sustained life-threatening injuries from the pit bull attack considered by Maryland’s highest court.

Under Zirkin’s initial amendment, an owner could escape responsibility if he could show that the victim had been attacked while trespassing, committing another crime, or provoking the animal. Otherwise, the owner could be held liable and, he said, the state eliminate the “one free bite rule.”

But the amendment was defeated. Zirkin then offered a second amendment, which would place the blame on the owner if the dog was running loose when the bite occurred, but that amendment also failed. On a motion for reconsideration, however, the second amendment passed 25-22, and Frosh’s amended bill advanced toward a final vote.