The National Association of Manufacturers has filed its lobbying report for the first quarter of the year without naming its members, citing its pending legal battle to overturn that new legal requirement.

On Monday, Chief Justice John G. Roberts Jr. rebuffed a request from NAM to delay enforcement of the 2007 lobbying law (PL 110-81). Two lower courts had already refused to issue a stay.

U.S. District Judge Colleen Kollar-­Kotelly upheld the law’s disclosure requirement in an April 11 ruling. Detailed reports were due Monday. But NAM, a trade group of 11,000 members, has appealed Kollar-Kotelly’s decision to the U.S. Court of Appeals for the District of Columbia Circuit. The appeal could take months.

The group, which contends that revealing the list would harm cooperation among its members, filed its first-quarter lobbying report with a notation citing its legal case at line 25, where “affiliated organizations” are supposed to be listed.

The filing refers to a Web page that states NAM is challenging the constitutionality of Section 207 of the law, which requires groups to name each member that contributes at least $5,000 to lobbying efforts during a quarter and “actively participates in the planning, supervision or control of such lobbying activities.”

“The Supreme Court stay request is over, but the Court of Appeals portion is continuing,” said Quentin Riegel, NAM’s deputy general counsel.

The stakes are high for NAM or any other trade group that would prefer to keep its membership confidential. Violation of the provision carries a maximum penalty of five years in prison and a $200,000 fine.

But punishment isn’t imminent. A lobbying entity has 60 days to correct a lobbying report after the Senate secretary and the House clerk notice a defect, according to the clerk’s Web site.

NAM, which fields about 35 lobbyists, contends that the law is too vague, failing to define how much participation is required by a member organization to require reporting. Its lawyers also contend that its list of lobbying members is a trade secret, and that once revealed, “the bell cannot be unrung.”

In denying NAM’s request for a stay, ­Kollar-Kotelly said delaying the deadline for the detailed lobbying reports could throw the disclosure scheme into disarray and confuse other organizations about their obligations.