Millions of Americans will be uniting in prayer today in observance of the 59th Annual National Day of Prayer.

Since 1952, when both houses of Congress passed legislation establishing an official Day of Prayer, Americans from various religious groups have used the observance to pray for their nation despite claims by a minority that such a day is an unconstitutional “establishment of religion.”

“This beloved observance brings together Americans stateside and around the globe who simply wish to pray for our land,” explained Shirley Dobson, chairperson for the National Day of Prayer Task Force.

President Obama stated, “Throughout our history, whether in times of great joy and thanksgiving, or in times of great challenge and uncertainty, Americans have turned to prayer. In prayer, we have expressed gratitude and humility, sought guidance and forgiveness, and received inspiration and assistance, both in good times and in bad.”

In his proclamation declaring Thursday as the National Day of Prayer, the president shared Americans have long deemed it “fitting and proper” to publicly recognize the importance of prayer on the National Day of Prayer.

Though it’s been only 22 years since Congress passed an amendment to the 1952 law designating the first Thursday of May as the annual National Day of Prayer, supporters of the observance point out how national days of prayer have occurred since 1775, when the Continental Congress asked the nation to join in a petition for divine guidance.

Since then, 34 of 44 U.S. presidents have called for days of prayer during times of crisis, noted Dobson.

“This has been the tradition of our nation from its founding,” she added.

Last month, however, U.S. District Judge Barbara Crabb struck down the federal statute creating the National Day of Prayer, concluding that it connotes endorsement and encouragement of a particular religious exercise.

"Defendants argue that the purpose and effect of the National Day of Prayer is to acknowledge the role of religion in American life, which is not objectionable," she wrote. "However, the line between 'acknowledgment' and 'endorsement' is a fine one."

Despite the ruling, this year’s observance are allowed to proceed pending appeal and the president has signed a proclamation again this year as he did the year before.

In his proclamation, Obama called upon the citizens of the nation to “pray, or otherwise give thanks, in accordance with their own faiths and consciences, for our many freedoms and blessings.”

He also invited “all people of faith to join me in asking for God's continued guidance, grace, and protection as we meet the challenges before us.”

According to a recently conducted USA Today/Gallup Poll, 4.5 percent of Americans said they were opposed to having a National Day of Prayer. About 56.8 percent, meanwhile, said they favored the observance, and 38.3 percent said it didn’t matter to them.