The Supreme Court on Friday denied an emergency appeal from the California-based antiabortion group behind the secretly recorded videos of Planned Parenthood officials discussing fetal tissue recovery.
The group, known as the Center for Medical Progress, had filed an emergency appeal asking the high court to allow it to keep its list of key donors and supporters confidential.
But Justice Anthony Kennedy, who oversees appeals from California, turned down the request.
The center is fighting a lawsuit from the National Abortion Federation, which alleges the center's members got into federation meetings by lying about themselves and falsely promising not to reveal what transpired.
In November, a federal judge in San Francisco ordered the antiabortion group to disclose who received "confidential information" involving the federation.
"It's time to end this shell game," Judge William Orrick said in a Nov. 20 order.
On Thursday, the 9th Circuit Court of Appeals refused to block the judge's order.
James Bopp Jr., a prominent free-speech and antiabortion advocate, filed the emergency appeal to Kennedy on Friday, saying the group was facing a midnight deadline to comply with the judge's order.
"The key issue here is the disclosure of the identities of CMP's supporters," he said, citing the "1st Amendment right of association."
The antiabortion group also argued that its lead investigator, David Daleiden, was a citizen journalist and is entitled to protect the confidentiality of his work and his sources of information.
But the judge rejected that claim as well.
On Twitter: @DavidGSavage