... A group of high school students attending a conservative leadership conference in Washington, D.C. said they were ordered by a security guard to stop singing the national anthem during a June 25 visit to the Lincoln Memorial.

"They told them to stop singing," said Evan Gassman, a spokesman for the Young America's Foundation. "I was taken aback. You wouldn't expect a display of national patriotism to be censored."

U.S. Park Police confirmed that the students were in violation of federal law and their impromptu performance constituted a demonstration in an area that must remain "completely content neutral."

"The area they were standing in and singing is an area that is restricted for this type of activity," said Sgt. David Schlosser. "The United States Park Police is absolutely content-neutral when it comes to any sort of demonstrations in these areas."...