Fairfax County police conduct a drunk driving checkpoint in 2006. Fairfax conducts at least one such checkpoint every weekend. (=Fairfax County Police Department)

FOR YEARS, Maryland law has coddled drunk drivers, a perversion of the public interest and a direct threat to public safety. For that, Marylanders may blame one man: Joseph F. Vallario Jr., chairman of the House Judiciary Committee in Annapolis and, not coincidentally, a trial lawyer who defends drunk drivers in court when he’s not defending them in the legislature.

While other states add muscle to their drunken driving laws, which have helped cut the number of liquor-related fatalities on the nation’s roads to a decades-long low, Maryland, in thrall to the liquor lobby, hardly budges.

This year, Mr. Vallario (D-Prince George’s) is again up to his old tricks. Although (or because) 14 of his committee’s 22 members have signed on as co-sponsors to a bill that would make it more difficult for repeat offenders to drink and drive, Mr. Vallario is refusing to allow a vote on the legislation. Similar measures have passed the state Senate in the past, but as long as Mr. Vallario plays the role of Obstacle in Chief in the House of Delegates, it seems unlikely that Maryland’s stance on drunk drivers will change.

The bill stuck in his committee would require that breathalyzers be installed on the dashboards of vehicles belonging to people convicted of drunken driving. The devices, known as ignition interlocks, would prevent drivers from starting their cars unless, having blown into a tube that yields an analysis of the alcohol level in their bodies, they proved to be sober.

Maryland has such a law on the books but, owing to Mr. Vallario’s influence, it applies only to drivers who are stopped when falling-down drunk , with blood alcohol content nearly double the state’s threshold for drunken driving . (In a 180-pound male, that would mean drinking a six-pack of beer, or six shots of hard liquor, in the space of an hour.)

Twenty-four other states, plus big chunks of California, require the devices for people whose BAC crosses the lower threshold, which means drunk enough to impair driving ability. In those states, liquor-related driving fatalities have fallen significantly, and in some cases steeply. Since a substantial number of liquor-related deaths involve people whose alcohol intake is less than the higher threshold for requiring the dashboard devices, there’s no doubt that the tougher law would save lives.

A Maryland task force recommended the tougher standards six years ago. Mr. Vallario was unmoved. His rationale is that it’s unfair to penalize drivers who might be merely “one drink over the line.” In fact, it’s unfair to penalize the victims of those drivers, who are among the 141 people killed in Maryland in 2013 in drunken driving accidents .

The more closely one examines Maryland’s laws, the more anemic they look. The vast majority of drunk drivers are excused with a slap on the wrist after their first offense, thanks to a state law that allows for probation before judgment. And research suggests that before an impaired driver is ever stopped by police, he’s probably driven drunk dozens of times and gotten away with it.

Chuck Hurley, a Marylander who has advocated around the nation for tougher laws on behalf of Mothers Against Drunk Driving, says his experience in Maryland, and with the power of the liquor lobby in Annapolis, is unique. “I have lobbied in 40 states, and I have never run into this level of lock by the good old boys,” he said. One boy above all.