ANNAPOLIS, MD: JANUARY 9 -- Governor Martin O'Malley. (Nikki Kahn/THE WASHINGTON POST)

SHORTLY BEFORE he signed legislation last year to repeal Maryland’s death penalty, Gov. Martin O’Malley (D) wrote the following, in Politico:

“Improving public safety is the most fundamental responsibility of our government. The death penalty does not make us stronger or more secure as a people. It is expensive, ineffective, and wasteful as a matter of public policy; it is unjust as historically applied; and its imperfections can and do result in the occasional killing of innocent people.”

Having convincingly made that principled case against capital punishment, it’s time for Mr. O’Malley to follow through by commuting the sentences of the four men who remain on Maryland’s death row before he leaves office Jan. 21.

To shift their terms to life in prison without parole is not only the right thing for the governor to do; it’s also, at this point, the only sensible thing to do.

Ever since a state court ruled in 2006 that Maryland’s procedures for lethal injections were unconstitutional, the state has lacked a valid regulatory scheme to carry out executions. And, having abolished capital punishment last year, it cannot now implement regulations to carry out a punishment that no longer is authorized by law.

As Maryland’s attorney general, Douglas Gansler (D), has noted, carrying out any execution in Maryland today would be “illegal and factually impossible.” Mr. Gansler, incidentally, is a proponent of capital punishment.

Lacking the legal authority and applicable procedures to carry out a death sentence, Maryland now faces the dilemma of four condemned men who exist in a legal limbo. State courts might conceivably revisit their fates. But in two of the cases, judges would be unable to impose a term of life without parole since that sentence did not exist in state law when the men were first convicted. And life with the possibility of parole is an unacceptable sentence in the case of men convicted of heinous crimes.

Only Mr. O’Malley can cut this Gordian knot. So far, he has been mum about his intentions. He has reached out to the relatives of at least two victims of death row inmates, at least one of whom urged the governor to leave the sentences intact.

To do so might insulate Mr. O’Malley from the risk of future Willie Horton-style attack ads, accusing him of coddling cold-blooded murderers. But leaving condemned men on death row when the death penalty no longer exists amounts to a bizarre act of make-believe punishment. It might also have the effect of affixing an asterisk to the governor’s legacy, which includes signing the legislation repealing capital punishment.

No state has ever executed a condemned inmate after abolishing its death penalty, and Gov.-elect Larry Hogan, a Republican, says he does not intend to revisit the issue legislatively. Mr. O’Malley had the courage to nudge the state toward repealing a punishment he considers ineffective and wrong. Now he should summon the courage to carry that decision to its logical end.