HERE'S WHAT has happened on Maryland's death row in the past few years.

One inmate's sentence was commuted, because Gov. Parris N. Glendening couldn't be convinced of his guilt -- despite two trials and numerous failed appeals.

At least four other convictions were overturned or vacated because of problems with procedure or lack of evidence.

A study has been commissioned to look into whether race taints decisions about who lives or dies in this state.

And now the U.S. Supreme Court has agreed to hear a Maryland case that could set a new standard for effective counsel in capital trials, thus casting even more doubt on several other inmates' convictions.

So it hasn't been a particularly reassuring stretch with regard to certainty. There have been more reasons to doubt the fairness of the system than to trust in it. Governor Glendening called a halt to executions this spring, saying he wanted to wait until the race study was completed before another inmate was killed. But he could have called the moratorium based on any number of apparent problems with Maryland's capital law.

That's why Gov.-elect Robert L. Ehrlich Jr. ought to hold off on his pledge to summarily lift the moratorium when he takes over next month. There are too many lingering questions, too many possibilities for error, to resume executions.

Mr. Ehrlich made his position clear early during the campaign, when he said Maryland's moratorium is not like the one in Illinois, imposed because several death-row inmates there were found to be innocent.

Technically, he's right; this state's current moratorium is not about innocence. But he's wrong to assume that Maryland doesn't have innocence problems. DNA evidence proved that Kirk Bloodsworth didn't commit a murder for which he was sentenced to death. Eugene Colvin-el had his sentence commuted because Mr. Glendening doubted his guilt. And two federal judges have written in opinions that death row inmate Kevin Wiggins is probably not guilty.

Mr. Ehrlich says if he lifts the moratorium, he'll consider each individual case as the inmate comes up for execution. He could go a step better, though, by declaring his own moratorium that's founded on a deeper inquiry into the state's capital system, to determine every possible problem with it, including the frightening frequency with which innocence questions arise.

The truth is that the system has committed glaring errors in recent years, and it could be only a matter of time before an error results in an unjust execution.

That would needlessly stain Mr. Ehrlich's record. He has been a thoughtful, not reckless, advocate of the death penalty.

He ought to build on that record by insisting that Maryland's capital system be fixed before it is allowed to start up again.