The National Prison Project was not involved in suits alleging violations at two other prisons where consent decrees were recently lifted: The Maryland Penitentiary in Baltimore and the Maryland Correctional Training Center near Hagerstown.
If Nickerson rules against them, ACLU officials will have 30 days to appeal the decision in the U.S. Court of Appeals in Baltimore.
Jenni Gainsborough, a spokeswoman for the Washington, D.C.-based National Prison Project, said it is "90 percent certain" the group would appeal.
She alleged that conditions at MCI and the House of Correction violate the U.S. Constitution.
Leonard A Sipes Jr., a spokesman for the state Department of Public Safety and Correctional Services, said the judge would not have lifted the consent decrees had the prisons not passed constitutional muster.
"We have always said that the state runs a constitutional facility," he said. "The state should have the right to run their own prison system without federal court interference unless there are issues of the Constitution."
Lawsuits in the 1970s and 1980s brought four Maryland prisons under the court's control.
The suits alleged a variety of abuses ranging from overcrowding to noise levels to substandard health care to prisoners' access to courts.
The major concerns at MCI, where 1,846 prisoners are housed, focus on health care for inmates.
ACLU attorney Karen Bower said a study from 1993 to 1995 revealed numerous violations of prisoners' rights. Sick inmates frequently were denied or delayed access to doctors; medication was interrupted; and surgery and emergency services were delayed, she said.
Bower said her interviews with more than 100 prisoners at MCI and the Jessup facility revealed similar conditions in 1996.
The state entered into the consent decrees to avoid costly litigation. Sipes said current state officials believe now it was a mistake not to fight them in court.
Lifting of the decrees gives the state flexibility and autonomy it did not have before, he said.
Gainsborough acknowledged that public sentiment is more hostile toward prisoners' rights than when the suits were first brought, but she criticized lawmakers for taking politically easy potshots at prisoners.