The National Day of Prayer (NDP), which will hold its 59th annual observance this year on May 6, is unconstitutional, a Wisconsin judge ruled on Thursday.
According to U.S. District Judge Barbara Crabb, the NDP "goes beyond mere 'acknowledgement' of religion because its sole purpose is to encourage all citizens to engage in prayer, an inherently religious exercise that serves no secular function in this context."
"In this instance, the government has taken sides on a matter that must be left to individual conscience," she added.
The ruling comes nearly two years after a lawsuit to ban the day was filed by the Freedom from Religion Foundation, a Madison, Wis.-based group of agnostics and atheists who hailed Thursday's ruling as a "sweet victory," according to the Huffington Post.
Meanwhile, the Alliance Defense Fund (ADF), an Arizona-based group of Christian lawyers, is urging President Obama to make an appeal to the "terrible ruling" which "not only undermines the National Day of Prayer, but the underlying heritage and tradition of the American people which dates back to the nation's founding."
"The National Day of Prayer provides an opportunity for all Americans to pray voluntarily according to their own faith--and does not promote any particular religion or form of religious observance," said ADF Senior Legal Counsel Joel Oster. "It does not violate the Establishment Clause of the First Amendment, and this decision should be appealed."
The tradition of designating an official day of prayer began with the Continental Congress in 1775, after which President George Washington issued a National Day of Thanksgiving Proclamation.
In 1952, President Harry Truman signed into law a resolution from Congress stating that the President "shall set aside and proclaim a suitable day each year, other than a Sunday, as a National Day of Prayer, on which the people of the United States may turn to God in prayer and meditation."
The law was later amended in 1988 by President Ronald Reagan, who designated the first Thursday in May as the official day for the observance.
The NDP received special attention from former President George W. Bush, who invited faith leaders to White House for a public service in the East Room eight years in a row.
President Obama, on the other hand, has taken a much more low key approach to the observance, and will issue a proclamation this year as he did in 2009.
"As he did last year, President Obama intends to recognize a National Day of Prayer," Obama spokesman Matt Lehrich told the Associated Press.