Gov. Martin O'Malley (D) on Wednesday named Mary Ellen Barbera, top left, as the new chief judge of the Maryland Court of Appeals, the state’s highest court. (State of Maryland/Maryland Court of Appeals)

Maryland Gov. Martin O’Malley selected the state’s first female chief judge Wednesday.

But perhaps more importantly, he chose one who has been an outsider in the court’s most liberal and controversial opinions in recent years.

Incoming Chief Judge Mary Ellen Barbera opposed the court’s decision, since struck down by the U.S. Supreme Court, to ban Maryland from collecting DNA evidence from arrestees.

She joined a dissent of the opinion that pit bulls are inherently dangerous, a unique ruling nationwide that threw thousands of Maryland pet owners into legal limbo with landlords and homeowners’ associations.

Barbera was also the court’s lone dissenting voice in a spring ruling that sex-offender registration can amount to after-the-fact criminal punishment — a decision that state officials warned could force them to remove thousands of sex offenders from Maryland’s online registry.

Barbera’s history on the court suggests that at least when it comes to public safety issues — long a top priority for O’Malley (D) — the Baltimore native could begin to moderate a court that had sparred increasingly with O’Malley and the General Assembly in recent years.

The sex-offender ruling could perhaps be the shortest-lived in Barbera’s court.

Barbera dissented in March when a plurality of the court declared sex-offender registration unconstitutional punishment for those who committed crimes before the registry began in 1995.

Under the ruling, Maryland corrections officials estimated that they could be forced to scrub almost one in four registered sex offenders from the online database.

O’Malley had signed the retroactive registration requirements into law in 2009 and 2010. At the time, he heralded the laws as significant accomplishments for public safety. Aides said he was dismayed when the court parted with the Supreme Court and most other states last spring in ruling that the registration violated offenders’ constitutional rights.

The court also framed the retroactive requirements as a violation of Maryland’s Declaration of Rights, not the U.S. Constitution, essentially making the decision off-limits to review by a more conservative Supreme Court.

As Maryland’s chief judge, Barbera will not only have greater sway over the court, but she could choose to replace one of the three judges who ruled in the plurality. That judge, John C. Eldridge, was a retired judge that outgoing Chief Judge Robert M. Bell chose to hear the case after another recused herself.

In a scathing 28-page dissent, Barbera called the plurality’s opinion “flawed” and concluded that registration does not amount to further criminal punishment, or ex post facto violations, for sex offenders.

Rather, she pointed to Supreme Court rulings on the topic that have held that registration is primarily a government scheme designed to ensure public safety.

“I see no merit in the contention that the online posting of information concerning the registrant’s conviction, his photograph, residence, etc., amounts to public humiliation and shaming, a traditional characteristic of punishment,” Barbera wrote. “Indeed, any such argument fails in light of what this Court and the Supreme Court have had to say on the subject.”