Next week, Americans across the country will take part in the annual National Day of Prayer. But one event on Capitol Hill closely associated with a Christian organization has come under attack.

An atheist group is demanding that no uniformed military personnel be allowed to take part in the event, claiming it violates U.S. Department of Defense regulations.

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Family Talk and Focus on the Family founder Dr. James Dobson joined Megyn Kelly to discuss the issue along with his wife, Shirley, who is the chairman of the National Day of Prayer. 

"The truth of the matter is that national days of prayer are an American tradition in history. There have been 44 presidents of the United States, and 34 of them have called for national days of prayer, including George Washington and Abraham Lincoln and Ronald Reagan. All but 10 in 200 years," Dobson said.

The Military Religious Freedom Foundation, led by Mikey Weinstein, is claiming that the event excludes non-Christians, and amounts to a government exclusion of non-Christians.

"We don't bar anyone from attending our event," Shirley Dobson said. "Any faith is welcome to attend."

The Pentagon has declined to formally respond to the Military Religious Freedom Foundation's request, and will provide a military chaplain to offer a prayer for the armed services during the event.