Without comment, the justices Tuesday turned away an appeal by retired teacher Judith Koenick, who argued that the rule violated the separation of church and state required by the U.S. Constitution.
Thirteen states have made Good Friday a legal holiday but only three--Maryland, North Dakota and Illinois--mandate that all schools be closed on Good Friday.
A federal appeals court has struck down the Illinois law. A challenge to Indiana's Good Friday law is pending before the justices, but they have not yet said whether they will fully review that case.
"This is not going away," said Dwight Sullivan, an American Civil Liberties Union attorney in Baltimore, the Associated Press reported. "You have the Constitution being applied differently in different states."
In her appeal, Koenick, who is Jewish, said the Maryland law "sends the message to non-Christians that the state finds Good Friday, and thus Christianity, to be a religion worth honoring while their religion or nonreligion is not of equal importance."
The 4th U.S. Circuit Court of Appeals ruled there is a legitimate purpose for the long weekend--the avoidance of anticipated high absenteeism among students and teachers on the days around Easter. Good Friday, which falls two days before Easter Sunday, commemorates the crucifixion of Jesus.
William Donohue, president of the Catholic League For Religious and Civil Rights, welcomed the high court's action but criticized the focus of the appellate court on secular rather than religious reasoning.
"It should instead have squarely faced the issue by saying that the Maryland law was accommodating--not sponsoring--a religious tradition that is grounded in our nation's history," he said in a statement. "Indeed, in Montgomery County, Maryland, schools properly close on Yom Kippur and Rosh Hashanah; this accommodates Judaism without sponsoring anything."
Maryland law does not mandate school closings for any Jewish holiday, the AP reported. The Montgomery County schools are closed on the first day of Rosh Hashanah, the Jewish new year, and Yom Kippur, the Jewish Day of Atonement based on findings that large numbers of students would be absent if schools were open at those times.