Pinellas Park, Fla. ? The U.S. Supreme Court refused to intervene in the Terri Schiavo case for the sixth time late Wednesday, taking less than two hours to reject her parents’ request that the feeding tube for their brain-damaged daughter be reinserted.

The one-sentence ruling came hours after the 11th U.S. Circuit Court of Appeals declined to intervene in the case. Justices did not explain their decision and there was no indication how they voted.

The Supreme Court’s decision, as Schiavo entered her 13th day without food or water, was the latest in a string of losses in state and federal courts for her parents, Bob and Mary Schindler, and the second time in a week the high court rejected the parents’ claims.

“We’re watching a black mark in American history,” said David Gibbs III, who represents the Schindlers. “Let’s just hope and pray something happens that will keep her alive.”

Schiavo’s husband, Michael, insists he is carrying out his wife’s wishes by having the tube pulled. It was removed March 18 after a 15-year legal battle, and Terri Schiavo, 41, was expected to survive one to two weeks without it.

The woman’s parents maintained that while Schiavo was weak, her organs were functioning Wednesday and she was responsive. They urged supporters to keep up efforts to reconnect her feeding tube.

“Under the circumstances, she looks darn good, surprisingly good,” Bob Schindler said after visiting his daughter Wednesday. “I’m asking that nobody throw in the towel as long as she’s fighting, to keep fighting with her.”