(CBS) Court action and the transfer of political power could taint recent victories by death penalty opponents in two states.

Over the weekend, outgoing Illinois Gov. George Ryan commuted the sentences of 167 condemned inmates, clearing Illinois' death row in a move unprecedented in scale in U.S. history.

That came a day after he pardoned four other death row inmates who had police allegedly tortured into confessing crimes they did not commit.

"I am not prepared to take the risk that we may execute an innocent person," Ryan wrote in a letter to victims' families warning them of his plans.

Ryan's action, just two days before he leaves office, drew immediate angry reaction from prosecutors, the incoming governor and relatives of some of the victims.

Incoming Gov. Rod Blagojevich, a Democrat, criticized Ryan's action, calling blanket clemency "a big mistake." Each case should be reviewed individually, Blagojevich said. "You're talking about people who've committed murder."

Now a country prosecutor has gone to court to try to overturn 10 of those commutations.

Cook County State's Attorney Richard Devine said his assistants Tuesday filed a petition with the state Supreme Court arguing that those death sentences had already been vacated in state or federal court and the inmates were awaiting re-sentencing.

"If a defendant is not sentenced, he is not convicted under the law and, hence, unable to be granted clemency," according to a statement from Devine's office in Chicago.

Five of the 10 inmates named in Devine's petition were convicted of killing two or more people.

It is not clear that Devine's case has any chance for success. CBS News legal consultant Andrew Cohen says Ryan's pardons are "irrevocable" — pardons and commutations usually are.

What are less permanent are moratoria on executions.

Ryan halted all executions in the state nearly three years ago after courts found that 13 Illinois death row inmates had been wrongly convicted since capital punishment resumed in 1977 - a period when 12 other inmates were executed.

Blagojevich has said he will continue the moratorium. But in Maryland, the incoming governor is expected to end a similar time-out for executions.

Outgoing Maryland Gov. Parris Glendening, a Democrat who did not seek re-election this fall, suspended all executions last May over worries the state's death penalty was biased.

But Republican Gov.-elect Robert Ehrlich, who was to be inaugurated Wednesday, has made it clear he plans to end the moratorium.

Once that happens, death warrants could be signed within a few weeks for at least two inmates.

The death penalty study, done by a University of Maryland criminologist, reviewed 1,311 death eligible cases between 1978 and 1999. It found prosecutors were most likely to seek death sentences for black defendants with white victims. The use of the death penalty also varied dramatically between Maryland's 24 counties.

Maryland has put three inmates to death since 1978, the latest in 1998.

Whatever happens in a Chicago courtroom or the Maryland statehouse, the significance of Ryan's move is still likely to be felt beyond Illinois' borders.

Cohen says, "This is probably the single most important event in the history of the death penalty since the mid-1970s, when the Supreme Court first outlawed and then reinstated executions nationwide. No governor, as near as I can tell, has ever commuted the death sentences of this many people, never mind doing it at the same time."

On Saturday, Ryan framed the death penalty issue as "one of the great civil rights struggles of our time."

"Our capital system is haunted by the demon of error - error in determining guilt, and error in determining who among the guilty deserves to die," Ryan said.